Wiring a fog light switch?

[Guest Anonymous]

On my tii parts car, there was a switch next to the ashtray, opposite the hazard switch. On the back there are four pins marked: +, 31, and two marked 'S'. What do the four pins do? It appears original, or a dealer item, but there were no wires connected in the back. Can anybody help?

[Guest Anonymous]

Many 02 owners want to install fog lights on their car, but wish to keep a stock and period appropriate appearance.

Unknown to many, factory fog lights were available. According to the HTK CD, there were several fog light switches and wiring harnesses available. These were mainly installed on French or Belgian cars, however I have seen a few US cars with the factory fog light switch installed. The switch is a round body similar in size to the hazard switch with a green illuminated lens. Give a press on the green dot to the right of your ashtray, you may just have the switch instead of the cover.

My first attempt at installing fog lights involved a very obvious wiring job and a dead battery as the fog lights could stay on even with the motor shut off. A properly operating circuit should only allow the fog lights to come on when the low beams are on. They should switch off when the high beams are applied or when the headlights are turned off. A clean installation can be obtained with a minimum of invasions using factory parts and some patience. Using my 72 tii as a test bed, here are my findings for wiring the fog lights. Your mileage and vehicle wiring may differ.

There are four connections on the back of the fog light switch: “+”,”31”,”S”, “S”.

The “+” connection goes to a switched +12vdc source. This is the control that should only allow the fog lights to be on with the low beams and not with the high beams. A good source for this is the yellow wire from the high/low beam stalk switch.

I used a crimp-on 3M nylon t-tap. These allow you to use an insulated ¼” quick disconnect for the new wire.

If you wish to run high powered driving lights to be on with the high beams only; you may tap into the white wire from the stalk switch. Further more, the yellow/white wire is live whenever the low or high beams are on.

The “31” connection goes to ground. A ring terminal can be connected on the left-side mounting stud for the heater box.

The “S” connection (either one) will then go to your control relay.

On the standard relay there are four connections. “85”, “86”, “87”, “30”.

The control wire from the fog light switch “S” connects to “86” on the relay.

The opposite side “85” connects to ground.

Connection “30” will be the supply +12v. This wire should be of proper size and fused. Usually connected to the bolt on the + battery terminal. In the Haynes manual and on my car, there is a connector into the white wires for the headlights. I would not use this as a power source for fog lights as this wire is only live with the high beams on.

Connection “87” supplies power to the fog lights themselves. The fog light bodies are usually grounded to the car body completing the circuit.

A round hazard switch connector may be used with the fog light switch. It is just a matter of removing and reinstalling connectors as needed to match the pin out of the new switch. The individual connectors press out once the locking pin is depressed. I have a small screwdriver that fits in perfectly. Bend the locking tabs back out and you are ready to reinstall. Wrapping the wiring with cloth electrical tape gives a nearly factory finish. It looks much better than the standard plastic tape and seems to weather well. Cloth electrical tape is available from many hardware stores. You can sometimes find older, round headlamp relays from some salvage yards. I mounted mine right next to the stock headlight relay and could switch should one fail.

The end result should be a fog light system that operates only when it is supposed to, and looks as the factory had intended.

[Guest Anonymous]

Thanks!!! I am not wiring fog lights, but I AM wiring up the fog light switch. awesome, detailed info!

put it on the 'faq man!

Matt

[Guest Anonymous]

(nt)

[Guest Anonymous]

More info than I needed, but that's a good, detailed description that should help anybody new to wiring.