by Rich Cwik
Have you ever had wiring problems in your Lotus? No, I haven't either. But Seriously folks, did you ever wonder why some of those wires are the color that they are? This information has been gleaned (that means stolen) from a variety of sources. Both inside and outside the club. When you're behind the dash, this may help a little.
There are four main colors in the typical British harness:
Brown - Wires are live all the time.
Purple - Are live all the time but fused.
White - Live when the ignition is on but not fused.
Green - Live when the ignition is on and fused, then feeds all the accessories, i.e. flashers, wipers, heater
All of the wiring that is not fused when the ignition is on is a white wire with a stripe on it. Therefore, the base color for the system is white.
White/Red - Starter Solenoid
White/Black - Ignition ground, switching side
White/Brown - Oil pressure guage
White/Purple - Fuel pump
All of the wiring associated with the headlight circuit is based on Blue:
Blue/Red - Dipped beam
Blue/White - Main Beam
Blue/Green - Main beam if fused
Blue/Black - Dipped beam if fused
All the side lights and auxiliary lamps are red:
Red/White - Instrument lights
Red/Yellow - Fog lights
Green/White - Right turn signals
Green/Red - Left turn signals
Green/Brown - Reverse lamps
Green/Black - Fuel gauge
Green/Blue - Variable resistance to ground, i.e. watertemp, heater blower, resistor.
Purple White - Map lights
There are some minor variations car to car, since some cars have integral stop/turn circuits while some have the Red stop amber turn signals, but this is usually a good starting point for your diagnosis.