Fog light wiring

[Andries]

Hi, can somebody please explain the fog light wiring of a 1993? I've opened the switch and found purple, yellow and a lighter yellow/white-ish cables. When I switch the headlight on I get 12v on the yellow/white-ish cable, then if I switch the fog light switch on I get 12v on the purple and yellow cables. What I would like to know is where is those two wires going? I need to wire a foglight on for the back because of British MOT so are hoping I can get a supply from that switch inside the engine bay and run it to the back, using one of the reverse lights with a red bulb in it. My Corvette was a export model, so it does not have the front fog lights anyway, but i'm hoping the wiring will still be there. The other problem is I need to do a opti change this weekend, but there is enough threads on that issue to help me My corvette was starting and cutting out on 180-190 temp, but now it is not even starting, throwing codes 16,36,42 (opti gone).
Thanks

 

[roger longman]

Hi andries, Another English guy here, living in California. I'm no use to you on this but I'm surprised no one else has chipped in. GMgunkie knows a lot so hopefully he'll come in to help and there are some other electrical whizzes who may know. Roger.

 

[ecss]

If you look at the fog lamp relay, 12 volts comes from the Tail 15 amp. fuse when the Headlight switch is in Park or Head and applied to the Fog lights when the relay closes.

The relay will energize when the Fog lamp switch is on, as long as the High beams are not on.

If the High beams are on, 12 volts will be on both sides of the primary coil of the Fog light relay which will not allow the relay to energize.

If the High beams are off. the 12 volts for the primary of the relay coil from the Fog lamp switch will travel through the headlight high beam filament to ground and the relay will energize.

The Fog light relay is located under the passeger side of the dash and mounted along the front bottom edge of the dash.