vw2p5

are those instructions for the protege5. To be able to turn the foglights on without having to have the headlights on?

njaremka

yes

djs2571

You can do this much more steath like if you have the wiring diagram... I'm attempting to attach pics of the needed pages if you want to make a circuit yourself. I hated that the fog's don't come on until your low beams are on - and the low beams negate the need or usefulness of the fog's, so i'm turning them on with the parking lights and off with the low beams.
In all cases shown here, you need the wire piece attached to the harness, not the connector. Make note where I say splice vs cut wire.

OK, so the cheap, easy, not much needed approach is to wire the fog switch directly to the fog relay ground - which bypasses the computer control that turns the fog's off with your hi beams.
This mod is done by cutting the black/red (black with red stripe) wire on J-04 position W (fog switch) and splicing it to J-02 position X black/red wire (fog relay negative). This is the ground side control for the relay, the computer control here can be pulled to ground without damage, just don't pull it high - or just cut the wire from the connector if you're worried.
But now the relay power is still tied to the headlight low beams, so this only allows the fog lamps to turn on when the low beams are on - which is how it is stock.
To keep the low beams under full control, you need to cut the red/black wire on J-01 position D (positive feed to the relay coil) and splice it to something like the running lights on J-01 position K (orn/blue) to allow the fog relay to be powered when the running lights are on, meaning that you won't forget and drain your battery with the fog lights on cause there's a beeper for your running lights. You could also splice to an ignition signal but it's farther away on J-03 pin AP (grn/ylw).

The sophisticated way is to make a circuit similar to what I did (attached schematic), that has an enable and disable line - so you can decide when the fog's will be controlled by the fog switch. I chose to tie the enable to the running lights which is also powering the fog relay positive, and the disable line to the low lights J-01 pin C (orn/wht), . The big reason for additional circuitry rather than just a relay adder that switches when you turn your low beams on, is that I added a delay, so if I want my fog's on, just turn on the running lights with the fog switch turned on and they come on in a few hundred milliseconds. If the fog switch is on and you switch quickly from all lights off to low lights on, the circuit will enable and disable before the delay expires, and the fog lamps don't turn on at all - saving relay contact life and bulb life.

To protect my circuitry, I added a 1n4004 diode across the fog relay - inside the case which prevents the back EMF from causing a voltage spike when it's turned off. The schematic shows 30V worth of zeners, which is technically a good practice for protecting the FET that I used, but there wasn't really a good amount of room to add that in, and there should never be voltage spikes that high in the system anyway.
I'm guessing there will be more q's on how to get this to work, so feel free to ask, I can add different schematic pages from the manual if needed.
Summary for wire locations:
J-01 connector - Low lamps right side - pin C orange with a white stripe
J-01 connector - Rear right parking lights - pin K orange with a blue stripe
J-01 connector - pin D - two wires - red with black stripe = fog coil +, orange with a green stripe = low lamp left
J-02 connector - fog relay ground - pin X black with red stripe
J-03 connector - ignition signal (didn't use this one) - pin AP green with a yellow stripe
J-04 connector - fog switch (switches to ground) - pin W black with a red stripe