Classic Car Electrical Wiring in Shropshire & Mid Wales

Classic vehicle wiring

Classic and vintage vehicle autoelectrical systems often feature more basic automotive wiring systems than modern vehicles with unique idiosyncracies.
Vintage british vehicle wiring systems may include bakelite switchgear, and a limited number of fused circuits. with occasional ignition and auxilliary circuits protected by fuses. Relays and Solenoids may be fitted to provide remote switching.

Typical classic vehicle wiring circuits use copper cored wiring with solid colour insulation on cables to supply power to switches.
Switched live from switches to components such as lights may be wired using cable with a solid + tracer colour insulation.

Wiring faults can arise due to component age and deterioration. Replacement parts may be obsolete and hard to source though classic car clubs can be a good source to locate rare components. Because old car wiring systems may lack adequate circuit protection, the fitting of additional fuses is often recommended to increase wiring protection and safety.

Classic vehicle electrical system voltage

Older Classic and vintage car and tractor electrical systems can feature different system voltage to modern vehicles, including 6 volt starting and charging. 6 Volt car electrical equipment can be particulary difficult to source. It may be possible to rebuild 6 volt starter motors and dynamos subject to component availability.

Magneto Ignition Systems

Magneto ignition systems are found on earlier vintage petrol motor cars and classic tractors with petrol engines such as the early wartime Fordson tractors.

Distributor and Contact Breaker Points Ignition Systems

Distributor ignition systems found on classic vehicle petrol engines feature a two stage ignition coil with primary low tension circuit switched by contact breaker points set to correct air gap. Dwell angle refers to when contact breaker points are closed. A secondary high tension circuit is connected to distributor cap centre terminal. A rotating arm (rotor arm) switches high voltage power between distributor cap centre king lead terminal, and the radially located cylinder lead terminals in engine firing order. High tension HT leads carry the ignition spark to spark plugs located in each engine cylinder.


Vintage vehicles may be fitted with a 'Dynastart' unit which combines an electric starter and generator. A v-belt is often used running directly on the flywheel periphery or on crankshaft pulley. Some dynastart versions may use chain drive. Dynastart units may be of four pole design with two poles carrying series windings for starting, and two shunt windings for power generation similar to a conventional series wound dynamo. If a dynastarter fails to operate check battery cell condition and electrolyte level, battery voltage and terminal connections, check for slipping belt, jammed or broken drive mechanism.


The series wound two brush dynamo output is controlled by a current voltage control (cvc) regulator often mounted in engine bay or bulkhead.

The earlier three brush dynamos may be found on certain vintage vehicles, where dynamo output is controlled by the driver moving the third brush position via a mechanical linkage and lever.

HT Ignition System

Classic and vintage vehicle ignition systems may include
HT ignition coil,
Ignition distributor with mechanical or vacuum ignition advance and retard adjustment.


Classic vehicles may feature vehicle lighting systems which do not meet todays road vehicle lighting standards but may be legally acceptable due to first use & date of manufacture or avoid Mot test regulations due to age.

Blast Cleaning & Welding

We have sandblasting sodablasting & welding equipment for restoration cleaning of classic vehicle parts

Specialist Auto electrical Fault finding, Rewiring & Component Repairs

Mobile autoelectrician service available for vehicle wiring service and repair to electronic and mechanical systems classic cars, commercials & tractors. Experience of working on a wide range of American, British, European and Japanese classic vehicles including Alvis, Audi, Austin, BMC, BMW, British Leyland, Buick, Commer, Citroen, Daimler, Dodge, Ford, Fordson, Ferguson, Fiat, Hillman, Humber, Jaguar, Jensen, Landrover, Lotus, Mercedes-Benz, Morris, Riley, Rolls-Royce, Rover, Sunbeam, Toyota, Triumph, Vauxhall , Volkswagen, Wolseley

British Rootes Vehicles : Positive Earth Wiring System : Typical Wiring Colours & Circuit Function

Some information interpreted from an old car wiring diagram dating 1940's. Different vehicle wiring diagrams vary !

to brush Fuel levelIgnition Coil to Contact Breaker CB (Points)Stop lamp switch, Fuel guage power, Sreen Wiper switch power
Wire No.Wire ColourFunctionComponent
1RedSidelamps, tail lights, Boot light, Panel lights rheostatLighting circuit
2Red & Yellow
3Red & Blue
4Red & White
5Red & Green
6Red & Brown
7Red & BlackDipper Solenoid Switch
8YellowD Dynamo
9Yellow & Blue
10Yellow & Green
11Yellow & Brown
12Yellow & Purple
13Yellow & BlackBattery Negative to Ammeter to Cigar Lighter fuse
14BlueLights H at Light SwitchHeadlights
15Blue & White
16Blue & GreenCigar lighter fuse to cigar lighter & switch
17Blue & Brown
18Blue & PurplePetrol gauge to tank unit
19Blue & Black
20WhiteIgnitionA3 Voltage Regulator, Ignition to Coil SW, Ignitio to push switch solenoid
21White & Green
22White & Brown
23White & PurpleF Dynamo to Ammeter A
24White & BlackA1 at Current Voltage Regulator, A at Light Switch
25GreenIndicators Trafficator
26Green & Brown
27Green & PurpleScreen Wiper Switch to Motor
28Green & BlackScreen wiper switch
30Brown & Purple
31PurpleHornPower to Horn
32Purple & BlackBrake lights, Fuel level
33BlackChassis Ground to Battery Negative
Autoelectrical Installation
M45G starter motor
Vehicle Security

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