Section XXII Wiring and Electronics

Wiring up a more or less completed car seems to be a source of major concern. This need not be so, as the basic circuits are quite simple if considered individually. There are just a lot of them !! The Appendices are provided mainly for non PWS looms as full details are supplied with the PWS loom. This section is probably the most complicated in the manual and you are advised to print off a copy and read it a few times until you are familiar with the contents.

I have built my car using a standard Premier Wiring Systems loom and have found no errors in the loom at all. The only faults were my own (2) and any errors in the text have been corrected accordingly. Builders using non-standard Instruments or Controls should proceed accordingly.

Note:- When removing any electrical items from other donor cars ALWAYS take the plugs and about 6" of wire. ie:- Mini Wiper Unit, Polo Fan/Heater, Citroen Radiator Fan and any non original Ignition Modules You will also need the Ignition Module plug, Brake Fluid Warning Level plug, Heater/Demister plug, Wiper plug, Distributor plugs, etc. Keep the Donor loom until the car is completed even if you have no intention of using it. While you are at the breakers get another Sierra Fan switch and the Air Vent. see below. Keep any rubber boots etc.Sierra Ignition Modules are becoming quite scarce, if you see one buy it, together with the matching distributor.

Safety Note:- It is a well known fact that most vehicle breakdowns are caused by electrical failure. Most of these failures occur on cold wet nights when you are miles from anywhere !! A lot more vehicles catch fire for the same reason. ( I know from experiance ) Always use cable of the correct diameter, ensure the terminations are electrically and mechanically sound and take extreme care to avoid any possibility of wires being chafed or trapped. As a 100% cure fit a hefty fuse on the main vehicle input wire. (Not in the Starter or Charging circuits) At least 45amps. In the event of a dead short this will blow and prevent any further problems. A trip type can be re-set, after you have found and fixed the fault. Some production cars are now fitting this type of fuse.

AS regards the actual wiring there are three options open to us:-

1) Rewire using new connectors and wire or salvaged Sierra connectors.

2) Use the existing Donor loom and connectors with all the unwanted wires stripped out.

3) Buy a proprietary loom. There are only two, Premier Wiring Systems and Vicki Green.

Option 1) may not be as cheap as it seems, buying small lengths of wire in a multitude of colours, together with crimp tools and connectors, if you can get them, may turn out to be quite expensive. Re-wiring to worn out salvaged plugs will take hours.

Option 2) is of course the cheapest, but remember that you are working with a worn out and dirty loom which may be up to 10 years old before you even start. Determining which wires to remove and which to retain may be easier said than done. This route could be a nightmare. Removing a complete loom from a Sierra in perfect condition is not as easy as it seems, some of the wire runs are very inaccessible and damage is almost unavoidable.

Option 3) is without doubt the best and the quickest, although it will of course be the most expensive, at least in the short term. It will however prove a sound investment and prove a lot cheaper in the long run. We are after all building a more or less brand new car, and it is a well known fact that electrical faults cause more roadside breakdowns than any other single cause. Being towed home on a wet night due to electrical failure is neither a cheap or pleasant experiance.

There is a lot of information on the RHOCaR web pages referring to options 1) and 2) but as far as I know, fitting one of the proprietary looms has not been covered in depth by an actual builder. I have decided to go down the Option 3) route and the following pages cover in detail fitting the Premier Wiring Systems Loom which is considered by many builders to be the best currently available, it is not the cheapest, but high quality never is. Incidentally, this company offers a one to one FREE help line, no waiting for e-mail replies that never seem to come. (Phone 01483 236 976) Hopefully this page should help you avoid most problems. There is a LOT of information, do not try to digest it all in one go. Print out a copy and read it a couple of times and when you are ready follow the text as you go. It is more or less in chronological order.

As we have mentioned before the Haynes Manual 903 covers the electrical side in great detail with plenty of wiring and component diagrams for all models. The first edition covers vehicles from 1982 to 1987 and the reprint covers 1982 to 1993. (Pinto SOHC, CVH, Injection and Twin Cam models) Do not take the pin positions shown in the component diagrams literally. They are wiring diagrams not engineering drawings.

One essential item of equipment is some form of continuity tester. A simple battery and bulb can suffice, but a more sophisticated digital multi-meter will not go amiss as this will also show poor connections (high resistance) etc. These can be bought quite cheaply at kit car shows, even Aldi do a very good one from time to time, we are not looking for precision measurement. If you wish to spend a bit more money you can get a similar meter that will also provide added functions such as a Dwell Meter, Rev Counter, Temperature Measurement as well as all the usual multi-meter features. A pair of wire cutters, strippers and a soldering iron etc. will be essential. Good crimp tools are expensive, but should not be required if you go for Option 3) as a crimp tool and crimps are now included in the Premier Wiring Systems kit. Connectors can always be soldered on. See also Appendix II Technical Notes

Wiring Loom Layout

Just as the final coat of paint can ruin a superbly built model, so can poor wiring ruin a good kit car, after all the cars reliability is almost 100% dependent on the electronics. If you lift up the bonnet on virtually any modern quality car it is hard to see any wiring at all. Just as a poor paint job ruins the outside, a rats nest of wires and tubes will ruin it under the bonnet. Try and keep all wiring down the cool, nearside, of the car and if possible tucked away out of site. Some of the better production cars even run the high tension ignition cables down a tube bolted to the cylinder head. Whether this causes HT leaks is another matter, but it seems to work OK and is very neat. There is not a lot you can do with throttle and clutch cables etc, but the runs can be kept as neat as possible and clipped in position. Keep your eyes open at the kit car shows to see just how well it can be done, it just takes that extra bit of care and attention to detail.

Wiring up the 2B using the Premier Wiring Systems Loom.

Before doing anything else check the date code on your Sierra column switch unit, see Appendix II Column Switch Unit. If you intend to use the standard Sierra Instrument Panel, advise PWS of this when you order, and state whether it is a 12 or 16 pin edge connector. PWS will supply you with the correct loom. I used a standard loom with no problems. But do bear in mind that the PWS colours are NOT always as per the Haynes manual. (Ford colours) Prior to fitting the loom it is a good idea to lay it out on the car and form some idea as to where the various electrical units will be positioned and a rough idea as to where the loom will fit. It is a bit daunting, but like a jigsaw, once you start the bits fall naturally into place. All must of course be within reach of the loom, and as far as possible, away from heat, vibration, moisture and dirt. Avoid these as much as possible and you will more or less ensure a reliable system. Note also that Estate cars had a Rear Wash Wipe stalk, not used in the 2B !! The switch could be used to operate something useful.

The PWS loom is more or less complete, but some items (special plugs) will still be required from the donor loom. Heavy duty cable is not supplied for the Battery or Starter links but cable is supplied for the Alternator to +ve battery connection. The PWS loom does NOT use the Sierra fusebox but the 4 of the old Sierra (or new) relays will be required. See also fitting the Gearbox and the Reversing Switch sub loom and plug. (rather an odd plug for some reason) This should have been fitted prior to fitting the Tunnel sides.

You will also note that there are no plugs fitted to the PWS loom for the Steering Column switches as these are no longer obtainable. The required plugs are cut off the donor loom and spliced into the PWS loom. See Appendix IV The colours are more or less as per the Sierra, but take care. There are seven (7) plugs on the column unit and thirty (30) wires including heavy Red and Blue/Black wires. At the base of each pin on the column unit is a number and this relates to the numbers on the PWS ' Finding your way ' sheet. See Lighting SW, Ignition SW 83BG or 87BG and Ignition SW on the PWS sheet.

The kit comes in two plastic bags and it is a good idea to check the contents against the supplied list to ensure that all the bits are there before you start.

A list is given below. See also the photographs.


(1) 1 Front loom with 11 wires. Blue socket.

(2) 1 Rear loom with 5 + 5 wires. 2 Orange sockets.

(3) 1 large Instrument loom complete with plastic connector's Relay and Fuse holders.

(4) 1 bunch of wires c/w connector's. 11 wires, 8 connectors.

Engine bay convoluted hose.

PVC Sleeving.


Crimp Tool Red.

Rubber Grommet.

Bag of connectors.

Loom plugs. 2 Red, 2 White, 1 Orange, 1 Blue.

Heavy duty Red wire. (4.5mm for Alternator)

Brown Earth wire.

Documentation:- Bag Contents sheet, Front loom notes (1), Rear loom notes (2), Instrument loom notes (3), Engine spur, Termination's options order form.

Large green plastic covered ' Finding your way ' notes.

The Termination Options sheet has lots of FREE items and instructions on the rear with ' Hints on the use of your crimping tool. ' You order these items on an as required basis. This enables you to match exactly the required termination at NO EXTRA COST. To save time and postage it is suggested that you sort these out prior to starting and order them all in one go. There is a list of the extra bits in Appendix IX required for a bog standard 2B plus only.

The looms are not marked but it is easy to relate the colours/number of wires to identify the Front loom (1) and Rear loom (2) The Instrument loom (3) is the one with all the Relay Holders and Fuses.

Lay the Instrument loom on the floor with the Fuses etc. on the left. Then moving from left to right, in conjunction with the " Finding your way" sheet we have 2 fuse boxes and 4 relay sockets (These will be mounted on the Firewall) You will notice that the relays have a number of crimps (8) not plugged into the relay sockets. This is deliberate as the 'pin-outs' on the relays vary, and you will need to configure these to suit the relays used.

You may, in the interests of reliability, wish to buy new relays as these are not expensive. Configuring the Relays will be covered in detail see Appendix III.

Then follows the N/s repeater socket, 7 wires into a White socket. Next is the Engine Spur = 12 wires. These are followed by one Blue and two Red sockets. Looms (1) and (2) attach to these. (Front loom and Rear loom) This is followed by 3 spurs:- 5 wires = Wiper, 3 wires = Reverse and Hand Brake (See note 1), 2 wires = Heater. Next is an 8 way Orange plug for the Instruments. See Appendix I below. Then 4 plastic covered links followed by the Dipswitch Spur =13 wires, Warning Light Spur = 11 wires, Ignition Switch Spur = 3 wires, Stoplight Switch = 2 wires, Foglight = 3 wires, O/s repeater = White plug. Earth wires to a ring tag, Wiper switch = 4 wires and finally Lighting switch 83BG or 87BG. See Appendix IV All these spurs and plugs should be identified with tie on luggage labels.

Note 1. These wires exit the loom in a rather odd position, more over to the nearside. Correct if you are just fitting the Handbrake Switch, but not so good for the combined Fluid and Handbrake switch (See Appendix I Miscellaneous) plus the Reversing Switch, which really need to pass through the Firewall on the offside, near to the Gearbox and the Pedal Box. Routing these wires AFTER the Firewall is in position is not easy.

Making a Start

There is a very good BASIC wiring diagram for this type of car in the Ron Champion book, page 134 Fig 13.52 This is NOT exactly as per the PWS loom but does give a good general idea of car wiring practice.

Fit the pre-fitted spade terminals on the end of looms (1) and (2) into the Blue (11 wires) and 2 Orange (5+5) wires connectors making 100% sure that all the colours match up with the loom. Double check as you go along, as an error here will cause endless trouble later on. See Photo. Once this is done the Front loom can be placed to one side in a plastic bag and marked up accordingly. The Rear loom can be fed down the Tunnel tube and left until required.

You are stuck with the location of most items, Starter, Alternator, Lights, Switches etc. But the location of the Electronic Ignition Module, Coil, Fuse/Relay holders and other misc. items needs to be selected with care. Try and keep the battery as close as possible to the starter motor. (short cable run, low voltage drop) The Ignition Module and Coil (whatever type you use) need to be positioned close to the Distributor. Fit a rubber cover over the starter motor live terminal. Mine failed on this point. see Section XXV The SVA Test.

It is a good idea to do a rough sketch of the engine bay and do some trial cable runs. When you are happy with the routing we can start to terminate the various items. Do not forget that some of the items require a proper earth, preferably to the tubular chassis with a proper ring tags and bolts, and that the earth wire is at least as big as the supply wire. Do not forget that the engine/gearbox will also require a substantial earth as it is largely rubber mounted, it is not a good idea to earth the starter through the throttle cable. This is usually done via a flat, very flexible multi-strand earth strap, at least capable of taking the full starter current. Where possible all cable runs should be fitted inside flexible trunking of a suitable diameter and clipped at regular intervals. (250 - 300mm intervals SVA) Do not cut and terminate any wires until you are 100% happy with the route. Final cutting and terminating should be left until you are totally happy with the layout. Leave wire spare to allow engine shake etc.

Instrument Loom and under the Scuttle.

The PWS Loom is mounted on the inside top of the Firewall, above the Heater unit with P clips, see photo, linking to the Column switches, Instruments, Wiper Motor, Illuminated Fog light switch, Brake switch, Handbrake Warning light, Reversing light and the Fan switch. The rest of the loom with the Relays and Fuses is brought through of the Firewall on the nearside. This makes sense as the Ignition, Starter/Solenoid and Battery are all on this side, away from the heat of the Exhaust Manifold. Items not on this side include the Alternator, Washer Bottle and Pump, Brake Light switch and Brake Fluid Warning switch. The large rubber grommet needs fitting to the loom. Not easy ! Fit from the Instrument end, as the relay holders will not pass thro'. Feed the Orange and White plugs thro' first, followed by the rest of the loom. Make sure it is the correct way round. The rest of the loom hangs temporarily into the bonnet area. I mounted the Heater matrix complete together with the loom onto the firewall, terminated all the plugs under the scuttle, and then fitted the complete firewall to the car. See Firewall section of the Bonnet page.

With the help of Appendix IV terminate the loom to the Column plugs and the Wiper plug. Appendix V gives wire colours for the Sierra wiper and the Mini wiper units. Before fitting the plug, feed the wire for the Handbrake Warning light under the carpet to the micro switch on the Handbrake. There is only one wire as this switch is an on/off to earth. The Foglight switch (which must be Illuminated for the SVA) needs to be mounted on the dash (use an SVA approved switch) and wired up correctly:-Grey Supply, Grey/Yellow to the Fog Light, Brown to earth via the warning lamp.

Finally terminate to the Sierra Instrument edge connector using the data in Appendix I. The connections to the VW Polo Heater Fan are covered in Appendix VI this also includes details of the Heater Control Illumination. The Polo fan has the speed resistors integral with the motor. Supply 12v +ve power via a 4 way dash mounted switch. Off/Fast/Medium/Slow. (use an SVA Approved switch)

Note that the PWS loom has sufficient wires to allow a complete custom Instrument Panel. ie: Separate instruments and warning lights. For this reason many of pairs include an earth wire. The Sierra Instrument unit has a built in earth at (Haynes) pin 12. When coupling up the warning lights to a standard Sierra unit do not include the earth wire. ie: Follow Appendix I

With the Firewall in position all the plugs under the scuttle can now be connected. Column switches, Heater, Wiper, Instruments, Fan switch, (the Sierra Fan switch is ideal for this application as it is illuminated, and has 4 positions, off, 1 ,2 and 3) Fog light switch (once again the Sierra Fan switch can be used as it can be wired for off, front, rear or both plus it is illuminated as required by the SVA) and Handbrake warning light. Before fitting see Appendix I Misc. Section. (poke a tube down the carpet and pass the wire down to the micro switch. We can now terminate the units fitted to the Instrument loom that are not under the scuttle. Brake Stop Light switch, (2) Reversing Light switch (2) and the Low Brake Fluid Warning Switch (3) Make sure this switch works before refitting. Mine was clogged up with dried brake fluid. The PWS Grommet is primarily designed to fit into a sheet metal firewall, so if you use a 19mm ply wall you will need to make up a dummy ring as per the photo'. The photo also shows the fuse holders and relay sockets fitted to the firewall, with the battery master switch to the left. After double checking all your work, making sure non of the wires can fray or short (tape down where possible) we can fit all the plugs followed by the dash. After fitting any heater pipes, control wires etc, his completes the electrical work under the scuttle.

Rear Loom

The rear loom is connected to the main loom by two Orange multi-way plugs.

We can now turn our attention to the wiring at the Rear of the car using the Rear loom. (which should have been passed down the prop-shaft tunnel earlier in the pre-fitted tube) This includes a Fog Light, Stop and Tail Lights, Number Plate Illumination, Fuel Tank Sender, Reversing Lights and Direction Indicators (Flashers) There are 10 wires in the Rear Loom with plenty of extra length. Full details of the termination's are given on the PWS Rear Loom notes but are repeated in Appendix VII Rear Loom. Since all the units at the rear of the car are new, with the possible exception of the Fuel Tank Sender, there are no Sierra colours to worry about. A Black/Yellow wire is also provided for a rear mounted fuel pump. This is not required if you are using the standard Pinto engine driven unit but make sure the end of this wire cannot cause a short as it is always LIVE with the Iginition ON. All wires should be sleeved and any that pass through panels must have tight fitting rubber grommets to keep out water and prevent short circuits. Clip all wires at regular intervals to stop chafing. (250 - 300mm intervals SVA) See photographs. The Rear Stop/Tail lights and the Fog light are in a very exposed position. Make sure it is impossible for water to get into the lights using gaskets and silicone sealant where required, water and electric's do not mix. It is a good safety point to ensure wires that may fall off cannot cause a spark. This applies particularly to the Fuel Tank Sender wires. The standard push fit connector was not used here but a 5mm locknut and ring tag was used. Some designs have a special Ford moulded plug on the sender unit, if possible fit this. Otherwise sleeve all wires. There is always the possibility of petrol vapour, but the open area under the tank should keep it well ventilated.

I have opted to fit two Fog lights, two Number Plate lights and two Reversing lights, together with the Indicator lights, Stop Lights and Tail lights all of which makes the wiring at the rear end quite complicated. It came as quite a pleasant surprise to find that all the lights worked first time, thanks to the excellent PWS loom. Most of these lights are switched on/off at other parts of the car, Gearbox Reversing Lights), Brake pedal, Indicator/Hazard relay, Dash and Steering Column switches. The earth wires were terminated inside the boot area well away from any dirt and moisture. All wires were well sleeved and supported as in the photo below. Refer to the SVA manual for mounting positions and also see the RHSC's brochure photographs. These give a very good idea of acceptable positions.

With all the Rear lights and the Fuel Gauge in full working order the rear boot cover was fitted and attention turned to the front lighting

In all diagrams the main wire colour is shown first followed by the thin trace colour. ie:- B/W is a Blue wire with a thin White tracer. A W/B would be a White wire with a Blue tracer. Colour codes are as per Haynes. (Ford) (2) indicates 2 wires etc.

Front Loom

This is connected to the main loom by a single blue multi-way plug and routed down the nearside chassis tube next to the engine loom. See Appendix X Front Loom from here wires are routed to the Main and Dipped Beams, Sidelights and Indicators. Also fitted are the side mounted Direction Indicator Repeaters. Before starting any actual wiring each circuit should be checked with a multi-meter. This ensures that any errors are at the "lighting end" and not buried somewhere in the system.


The headlamp platforms are unavoidably distorted during welding and this has proved more or less impossible to polish out. Two pieces of stainless steel sheet were cut to the same shape and fitted on top of the lamp platforms. These are secured by a very thin layer of structural adhesive and the edges hidden with snap on edge beading. The 4 wires to the Headlamp units are sheathed in chrome plated flexible conduit (B&Q Shower Hose Part No.285-0120-CP 1.25m x 8mm) and passed through the side panels. The existing end fittings are cut off and new ones manufactured from suitable alloy bar. Do not remove the internal plastic sleeve as it supports the spiral. see AutoCAD drawing. The o/a length of the new conduit is 12". The threads on the headlamp pillars are 1/2" x 13 unc. See photographs below.

The 3 way plugs fitted to the sealed beam units can be discarded. The colours for the wiring on the RH Side Light Adaptors are as follows. Red to Sidelight, (Grey/Red or Grey/Black). Top Pin - Blue/Red, Dipped Beam (Yellow). Right Pin - Blue/Grey, Main Beam (White) and the Left Pin - Black is the earth for all 3 bulbs. Colours in ( ) are the corresponding connections to the PWS Loom. see also the table in Wiring Appendix X Do not forget to fit a substantial earth from the Black wire to chassis. The wires fitted to the RH Side Light Adaptor plug look a tad thin to me, they were probably intended for lower rated headlamps. (Austin/Rover Mini) Do not forget that your Headlamps will need Alignment. Before you start there is a minor problem here. The triangular headlamp platforms are not parallel to the road, due no doubt to welding distortion, and it is almost impossible to align the sealed beam units in a true horizontal plane. This was easily cured by opening out the three notches in the headlamp rims, where the registers on lens fit, allowing the lens to rotate just a tad more. 4mm was sufficient.

Conduits fitted
Detail of Conduit


There is no actual provision in the Robin Hood kit for sidelights, although a reference is made to them in Video D. The sealed beam units have a small circular window in the reflector and a special adaptor plug is required. These can be obtained from Robin Hood. (see page 45 Sidelight Adaptor) This unit plugs onto the 3 prongs of the sealed beam unit with a sidelight bulb underneath. Four wires exit the headlamp Main, Dipped, Sidelight and Earth. Moss Europe Ltd. offer a similar item as an Austin/Rover Mini spare but it is a tad more expensive.

Direction Indicators

The direction indicator stalks on the nosecone must EXTEND to within 400mm of the outermost body panels. Do not forget that the REAR mudguards project further out than the FRONT. (SVA requirement) Locate as per the many brochure photographs. Note that if you have fitted 61/2 J wheels the rear mudguards will be at least 25/35mm further out. The units supplied with my kit do NOT comply, being some 100mm too narrow. Yet another instance of RHE getting it wrong. This will entail the manufacture of two complete new units or the fabrication of a pair of washers approx 60/70mm thick c/w a couple of bolt extensions. The nuts (not supplied with the units) are rather an odd size, M10 x 1.25mm. The side repeaters were fitted below and forward of the windscreen using self adhesive patches and 20mm spire nuts, again with reference to brochure photographs. The special plugs c/w locking clips came off the donor vehicle.


A pair of Italian 12v Sprint Air Horns are fitted on the top front suspension cross member, the air pump and relay are mounted some distance away on the firewall, the kit from Premier Wiring Systems, comes complete with 2 horns an air compressor, relay, pipes, and all fittings. Fit the horns so that any rainwater cannot get in or runs out easily. See photo. Note the compressor requires a few drops of oil occasionally. Determine which type of switching is used for the horn, switched live or switched earth and use the appropriate colour and follow the instructions in the kit or see Appendix X Front Loom Check that Air Horns are acceptable for the SVA. The multi tone musical horns are now illegal on vehicles registered after 1973, as are very loud horns. (check out this date) A wiring diagram is given for a pair of Air Horns c/w Relay & Compressor in the AutoCad zip files. (switched earth)

Detail of Air Horn Mounting

Engine Bay

Coming through the firewall is a single blue plug, two orange plugs, plus the fuse and relay holders. There is also a long tail of twelve (12) wires. This is the engine bay loom. Colours as follows:- Main supply medium Red, (from pin 30 on the ignition switch) Ignition Warning light Blue, Starter Solenoid Black/Green, Rev Counter Light Green, Water Temp Brown/White, Oil Warning Brown/Green, Oil Pressure Gauge (if fitted) Blue/Red, Low Brake Fluid Brown/Yellow, Earth Brown, Windscreen Washer Supply (83BG) Black/Red or Windscreen Washer Supply (87BG) Black/Blue, Switched Earth for the Windscreen Washer Supply (83BG) Black/Blue. (83BG) and (87BG) refer to the type of steering column switch fitted. (See PWS notes)

The first thing to do before we even consider doing any wiring is to fit (or recheck to ensure they are already fitted) all the under bonnet electrical items. These include the Ignition Module, Distributor, Engine Sensors, (Water and Oil) Thermo switch for fan, Fan unit, Alternator, Starter Motor/Solenoid, all Fuses and Relays, Horn, Washer Pump and Bottle, Brake Fluid level switch, (on the Fluid Reservoir) Brake Light switch, (on the Pedal Box) Reversing switch (on the gearbox) and the Battery. Once all these items are in we can consider the cable routing. This is important for a number of reasons. The aim is to keep cable runs as short as possible, but out of extreme heat, dirt and moisture, and to make an aesthetically good job that looks neat and workmanlike under the bonnet. A rats nest of wires looks awful and sooner or later will fail. (many cars fail the SVA for poor, unsafe wiring)

Battery Master Switch

The SVA regulations require the fitting of an engine immobilizer, electrical or mechanical, independent of the ignition switch. This is covered by fitting a battery master switch and as a bit of a backstop, a fuel cut off valve as well. To keep cable runs as short as possible the car has been wired as follows:- 1) Run a heavy wire (37/0.09) from the battery +ve to the starter motor, not the solenoid terminal. 2) Run a wire (97/0.03) from the starter motor to the battery master switch input. 3) Run the main charging wire (97/0.03) from the alternator to the starter motor, or to the battery master switch input or even the battery +ve. Run the blue wire from the alternator to the ignition warning light. All other wires, where required, such as the medium Red on the PWS loom go to the battery master switch output. Turning off the battery master switch will remove power from the ignition, starter solenoid, and the anti run-on valve if this is fitted, this will stop the engine dead. The choke will remain open as long as the engine continues to run as it is driven off the alternator. The switch is NOT an anti-thief device, as it is a simple matter to short across the two terminals. Fitting a substantial insulated bolted on cover over the switch will make theft just that bit harder. But no car is thief proof.


An ideal location for the battery is at the end of the passenger footwell, adjacent to the starter motor. There is just enough room to get a decent size battery in here. The lower chassis side rail and the engine mounting tube make a really substantial support for a battery platform, and the rear edge of the platform is bolted, via an angle bracket, to the lower part of the front footwell panel. (the front footwell panel could be cut from slightly thicker material). This low position gets the battery close to the starter motor and gives an ideal centre of gravity position. This leaves the area over the passengers legs free for relays, fuses, horn, etc. I made the battery platform from a piece of 8mm marine ply, a very rigid material, and sat a 16swg stainless steel battery tray on top of this. The tray was formed exactly the same size as the battery base, with 12mm sides and this stops the battery sliding around as the tray is secured to the ply platform with 5mm c'sk screws. See photographs and Appendix II Link to AutoCAD Drawings for a drawing of the battery tray and platform. (The idea for this location came from Tony Hurst NWRHOCaR) A couple of clips hold the battery firmly down. Also shown in this photo' is the engine earth strap location. This is a standard 25mm wide flexible belt fitted with two 10mm eyelet's. Fit coloured Battery Terminal Covers to the +ve and -ve terminals. (these are required by the SVA)


There are three wires coming out of the special alternator plug, two medium Reds and a Blue. The Blue goes to the ignition warning light via the PWS loom. The two medium Reds can be joined together, close to the alternator, and a single heavy Red (supplied in the PWS kit) runs direct to the battery positive (+ve) or to the 8mm terminal on starter motor. (NOT the solenoid terminal) This is a fairly long cable run, keep it away from heat and moving parts. Use the correct heavy duty terminals and crimp or solder, rubber boots are available for the terminals, this prevents accidental shorts and keeps out the dirt etc. For added safety sleeve these wires exactly as per the donor. There is a 4th terminal (the insulated one on its own, thread M5) colour Blue/White, this supplies 12 volts +ve only when the engine is running, and runs directly to the electric choke on the Weber carb, if fitted. The choke will not operate, even under extensive cranking, or with the ignition left on. Once the engine fires and runs the choke will start to open. As soon as the engine stops the choke will start to close. Haynes show a diode in the ignition circuit (Blue wire) to prevent reverse current flow, this is thought to be superfluous.


See Appendix VIII

Ignition Coil

The Ignition Coil is mounted on a custom bracket fitted to the chassis, adjacent to the Distributor. New Spark Plugs were fitted (NGK 2922 APR6FS) together with a new set of Ignition Leads. (Champion Part No. LS-09 to suit 1.3, 1.6, 1.8, 2.0 Litre Pinto OHV and others) The Coil to Distributor HT lead is far too long but with a bit of CARE it can be shortened. Leave enough to allow for engine shake. Full wiring details are given in Appendix VIII

Ignition Module

This is bolted to the vertical passenger footwell end panel, with a coating of heatsink compound on the joint to aid heat transfer. Full wiring details are given in Appendix VIII These modules (particularly the preferred Type 83BB) are becoming quite scarce as they were fitted to the earlier models. Builders are advised to get a spare as soon as possible, whatever type you use, together with the coil and matching distributor. They can still be found in breakers yards but for how long, if you see one buy it.

Starter Motor

The Starter Motor has 2 terminals, (a) Motor windings, Heavy Red direct from battery +ve and (b) Solenoid, This terminal is the one that links to Black/Green on the basic Amplifier with a second wire, Black/Blue running back to Pin 50 on the Ignition Switch.

The photographs show the wires routed down trunking clipped to the top nearside chassis, with spurs off to the various units. Where possible I have used the original Ford terminals, usually push on with a rubber cover, and solder spliced onto the ends of the PWS loom. I am not sure about the electrical integrity of these old plugs, I prefer a nut c/w washer and ring terminal, but they seem waterproof and will do at least until after the SVA. They worked fine on the Sierra !! As my carb has an Anti run-on valve the Black wire from the Amplifier to the Coil +ve was spured off to the valve on the Weber carburettor. Otherwise all wires were as per the PWS instructions. Wires not used should be cut short, fitted with a blind crimp and taped up safely out of the way.

This more or less completes the engine wiring apart from the fan, which feeds off the Purple wire on the front loom. See also Section XVI The Cooling System and Fan. Turn on the Ignition and the engine should run, fuel and oil will however take quite a few turns to fully prime the system. It is a good idea to fill the float chamber with petrol first. Do not forget to fill with Oil and Water and remember that the Cylinder Head bolts will require a final tighten after 15mins running. Ignition timing details are covered in the Des Hammill's Speedpro Book and also in the Haynes manual. Typical idle speed advance is 12 degs btdc at 600 - 700 rpm for Leaded 4 star 97 RON and 8 degs btdc for unleaded 95 RON.


Apart from getting a couple of wires crossed on the Instrument edge connector and getting the initial firing order wrong, (quickly sorted by Alan at PWS) it all fired up more or less trouble free.

Main loom kit Premier Wiring Systems

Front and Rear looms PWS

Instrument loom fitted to the firewall.

Detail of Exit Bush

More PWS loom detail

View of main engine bulkhead in position

Detail of loom exit to engine bay

Rear Lights

Click on the thumbnail for a larger image.

Table of Appendices:-

Appendix I The Instruments

Appendix II Technical Notes

Appendix III Configuring the Relays

Appendix IV Steering Column Switches

Appendix V Wiper Connections/Mini/Sierra

Appendix VI VW Polo Heater Fan Connections

Appendix VII Rear Loom Connections

Appendix VIII Transistor Ignition Module Connections

Appendix IX Extra bits required

Appendix X Front Loom

Appendix XI covers Dashboard conversion to Individual Smith's 'Classic' Instruments

Go to Section XXIII

Copyright Text Colin Usher 2011 Illustrations Colin Usher 2011

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