Locust Wiring

Based on an article at

General Points

If you are using the wiring loom from an existing car you should be able to simply plug in the components and switch on. You may have to modify your loom because the loom does not fit your chassis i.e too long, or you want to fit additional components or you want to remove the wires for components you haven't fitted.


When you take the loom out of your donor car it is really essential to label all the connections as you go. You can do this with bits of white insulating tape and a permanent pen. Don't rely soley on the circuit diagram of your manual as there may be differences.

Renovating and installing a loom

The old wrapping will be dirty, it could hide all sorts of badly-done repairs and breaks. Take the opertunity to take the wrapping off and replace it later. Leave on the tapes you will find underneath at junction points - otherwise the whole thing will collapse into a tangle. You should find once the loom is bare that you can see what goes where and how the system fits together, which makes life so much easier. Once you start putting the loom into the car, do it without re-wrapping it so that you can adjust exit points of wires from the loom, put in extra wires (e.g rear fog lights) and remove ones you don't need (rear window heater, courtesy lights). Tape the exit points where wires come out of the loom. Get all the connections sorted. Then with everything connected, test the whole lot. Then you can re-wrap the loom, using non-adhesive pvc tape. - you don't need to take it out of the car to do this. Don't forget to put grommets onto the relevant parts of the loom before you put all the connectors on and before you wrap it.

Escort Wiring Loom

There are colour codes for vehicle wires. In fact there are several sets of codes - older British cars have one set, older continental cars like the Escort have another (DIN standard), and this seems to have changed in more recent cars. The main colours in the Mk1 and 2 Escorts are:

Colour Main uses Examples
Red - direct supply from the battery, always on. Starter cable from battery
Cable from Alternator to battery and ignition switch
Supply to steering column switches for lights
Supply to courtesy lights and clock
Black switched supply (and negative battery lead) From Ignition switch position 2 to components which are only on when ignition is on.
The supply wire for the reversing lights is black.
Black / yellow ignition circuit supply to coil, tachometer, instrument voltage regulator
Black / red ignition switch start position to starter solenoid
    (also) brake lights
Black / green offside indicator  
Black / white nearside indicator  
Black / green / white supply to indicators  
Black / blue supply to washer pump (can also be supply from ignition switch to solenoid)
Brown all earth wires (to chassis)  
Brown / yellow,
Brown / green,
Brown / white
switched earth (I think) circuits where the switch is on the earth side of the circuit rather than on the supply side - parts of the heater circuit, the brake warning light circuit and bits of the wiper delay.
Grey sidelight / panel light supply divided into - see below
Grey / yellow panel lights  
Grey / white nearside side lights  
Grey / red offside side lights  
White headlight main beam  
Yellow headlight dipped beam  
Blue / black fuel tank to fuel gauge  
Red / white temp. sender to temp. gauge  
Blue / green oil sender to oil warning light  
Green wiper supply slow speed
Red wiper supply high speed
Pink / white ballast resistor wire to coil  

You may have a serviceable battery. If not you can buy one for about £40, Don't mess about with second hand units from scapyards.


The Escort loom may be too short to reach the headlight units. You cantake a pair of headlamp looms from a Mini: they have a bulb holder for the sidelight which then lines up with the gap in the reflector of the standard Escort round sealed beam unit, which means you don't need separate side lights. The wire colours for this part are: black = earth, red = sidelight, blue / red = dip, blue / white = beam.

Repeater indicators

Some posh Escorts had these but most did not. hey should be wired in with the front indicators, by connecting feed wire to feed wire and earth to earth.


Assuming you are using a BL wiper motor, you have the problem that the wire colours are different to those on the Escort.

The Escort has five wires to the wiper motor, in two groups - two power wires (green and red, from the column stalk) which have a grey plug, and three other wires via a black plastic connector to a headlamp-type plug on the wiper body (these are the motor earth and the park wires).

The BL motor also has five wires doing the same jobs, going to a 5-way multi connector with 4.8mm female spade terminals which plugs into the wiper unit. You should cut off this connector with as much wire to spare as possible when you get your motor from the scrapyard. You can remove the wires from it by poking a small pointed object into the business side of each terminal - there is a small cut-out - and bending the non-return lug flat. This allows you to use new terminals. Or, you can leave the wires in place and make soldered connections to the Escort wires.

The big question is, which Escort wire to which BL wire? OK - BL black is the motor earth, which goes to Escort brown / white. Escort green is low speed, and goes to BL red/green. Escort red is high speed, going to BL blue/green. Escort black/violet is the park power supply and goes to BL green. Escort black/brown is the park earth and goes to BL brown/green.

If your Escort has a wiper delay (marked on the column stalk, plus you have a large red relay like a flasher relay) then this will work fine with the BL motor. Its wiring isn't detailed in the Haynes manuals, so I can't help if you don't have one but want to add one.

Dashboard switches

There are many ways to connect the various items that were controlled from the stalk switch on the Escort. Most people use individual dash mounted switches for the various components but beware of the SVA requirements the old type of toggle switch can not be used. You will have to source the safer rocker switches.

Hazard switch

Your hazard lights must work with the ignition off or on. The original Escort loom uses only one flasher unit to work indicators and flasher, and does this by having a special switch. The switch has seven terminals: 1: flasher unit feed (two terminals, a black/yellow feed wire and a black wire to the flasher unit) which is "on" when the hazard lights are off), 2: battery input (two terminals, a red and a brown which gives power to the flasher unit when the ignition is off) and 3: hazard flasher supply (three terminals, a black/white/green input from the flasher unit and two outputs to the lights, black/green and black/white. The switch keeps the battery input and the hazard flasher supply groups of terminals separate (otherwise the hazard lights would be permanently on). If possible use this switch.

A standard after-market hazard switch has only six terminals, in a group of two and a group of four. You need a separate flasher unit for your hazard lights if you change to one of these switches. Proceed as follows: take a battery feed (red) wire to the B terminal of the new flasher unit, and put in a new wire from the L terminal to the new switch. Connect the two wires which were on the old flasher unit feed to the pair of terminals on your new switch. Lose the black/white/green wire (cut it off short and tape it back into the loom). Connect the remaining three wires (black/green, black/white and the red supply wire) to any of the four other terminals (I mean one terminal per wire, not all wires to one terminal!). If your new switch has a telltale lamp, take a short wire from the fourth terminal to the positive side of the lamp, and an earth wire from the negative side to earth.

Rear Lights

There are many ways of getting a set of rear lights, such as buying a trailer lighting board. For SVA purposes you must have: indicators, stop lamps, tail lights/rear side lights, a rear fog light and two reflectors.

Electric cooling fan

Assuming you are putting in a cooling fan and using a x-flow engine, you should have got a Fiesta (or similar) temperature switch in the thermostat housing you found in the scrapyard. To get this to control your fan you could just wire a supply to one side of the switch and the other to the fan, taking the earth lead from the fan to the chassis (after checking the fan is blowing or sucking as required). However you ought to use a relay to switch the fan on and off. You need a simple (and cheap) 4-blade relay - The relay will have the following numbers on the terminals: 30 (supply from ignition switch terminal 30, i.e. on when ignition is on), 87 (output to fan), 85 and 86 (switching current - it doesn't matter which terminal is wired "live"). Proceed as follows: run a cable from the black terminal of the ignition switch or from the fusebox to the relay terminal 30. You ought to have an in-line fuse in this cable. Connect the output from terminal 87 to the fan input, connect the fan output to the chassis. Connect a similar feed wire (which could be the same one) to the control input, terminal 85. Connect terminal 86 to one side of the temperature switch, and the other side of the temperature switch to earth. Do not connect the fan circuit (heavy current) to terminals 85 and 86, as this won't work.

Dashboard (adapting to non-Ford instruments)

The dashboard wiring tends to get messy because unless you have a removable scuttle it is hard to get at. The main bits are:

Panel lights and earth: You should have panel light feed wires (gray/yellow) hanging out of the dash area of your loom - they often get cut and adapted in the life of a car as accessories are added and removed. They go to the panel lights, preferably only using one wire to keep the mess at bay. Depending on the instruments you are using, illumination will differ. With after-market gauges or salvaged Smiths ones, the panel lights sometimes have a red feed wire and black earth wire because of the old British standard system. If you want dimmable panel lights all you need to do is find a dimmer switch in a scrap car and wire it into the FEED wire. Don't put it in the earth wire unless you are sure no other dash components are using that particular wire.

Voltage regulator: Screwed to the back of the Escort instrument cluster is a small rectangular box, probably a bit rusty. This has two springy brass contacts on it. This unit is the instrument voltage regulator, and governs the voltage used by electrical gauges (fuel, temperature etc). It has an input and an output terminal (input is right-hand side as you look at the back of the Escort cluster), and if you connect it back to front it won't work. It needs to be fixed somewhere under the dash, and you then connect its original black/yellow feed wire to the input and a feed wire from the output to the various gauges' input terminals. You can use 6.3mm spade connectors on the unit if you snip off the bent-back part of the terminals.

Tachometer: These instruments use the pulsing of the ignition circuit to show engine speed. There are 2 types of tacho you may meet. The older Escorts had one continuous wire from the coil negative terminal through a sensor on the back of the tachometer and back to the distributor. Some Smiths tachos use the same system. Happily, later models are more sensible: they have feed wire (black/yellow) and a trigger wire (should be green), the trigger wire coming from the coil negative post but not going back to it.

Telltale lights: When you took your loom to bits you marked the connectors, of course. The one or (for tacho-equipped cars) two instrument connectors are as follows: tacho trigger (green), tacho supply (black/yellow), panel light supply (grey/yellow) and earth (brown) make up the smaller connector. The bigger one has: panel supply and earth (as previously), indicator telltales (right is black/green, left is black/white), beam telltale (blue/white), fuel sender (blue/black), temp sender (red/white), voltage regulator feed (black/yellow), oil pressure sender (green/blue), charge warning sender (blue). If you want to use alternative telltale lights, you need only wire the relevant sender wires to one side of your new lights and the other side to earth. The exception to this is the oil pressure light, since it earths through the engine block. This circuit needs a live feed to its telltale lamp (it uses the voltage reg. feed in the original dash) and the blue/green wire goes to the negative side of the lamp, thence to the sensor on the engine.

Fuse Box

If possible fit the origional Escort fuse box. Because the connectors to the box are moulded onto the loom I would not advise getting an after-market fuse box.

Starter and solenoid

If you are staying with the Escort engine and gearbox simply mout the Escort solenoid some ware suitable.

If you want to change an inertia starter for a pre-engaged one (if you are using a Sierra gearbox), you won't need the old solenoid because the pre-engaged starter has the solenoid mounted on it. After you have finished modifying your Sierra engine backplate to get it to fit your x-flow (the x-flow plate starter holes don't match a sierra gearbox) you need to make the connections as follows: red battery cable - the big one - to the big terminal on the starter solenoid, and the black/red cable which was connected to your old solenoid, which runs from the ignition start position, to the small terminal. There is a third terminal on the solenoid, but it is the output to the started motor and should not be touched.


There are several sections of the SVA test which affect the electrical system.

Lights and position of lights: You must have the obvious lights (indicators, hazard lights, headlights, sidelights, stop lights) and also a rear fog light. The units must either be E-marked or else give an light equivalent to an E-marked unit. There are detailed instructions for the position of lights relative to the sides of the vehicle and to the ground, and angles of visibility - you really need the SVA Tester's manual for this, but you ought to get it anyway.

Security / tidiness of wiring: Untidy wiring, poor connections or lack of protection for the loom from abrasion or heat could all be failure points, as they could for an MOT test.

Compulsory components :

A brake fluid warning light which is visible to the driver and which illuminates when the level in either brake circuit is low. The light must be fitted with a test switch to allow you to test the warning bulb.

A hazard light circuit with a switch which has a telltale light visible to the driver.

A rear fog lamp whose switch has a telltale light visible to the driver. The fog lamp must not operate in conjunction with the stop lights.

Telltale lamps for left and right indicators and for main beam (visible to the driver).

Stop lights operated from the brake pedal or brake fluid pressure.

Dashboard projections: When you choose switches, remember they are not allowed to project more than 5mm from the dashboard in most instances, which means you need rocker switches.

Most British cars tended to use the Briish Standard BS-AU7 to deturmine the colour of wire to each component Lucas used this. A list can be found here. Lucas wiring Colours