electrical and ignition Foglight Wiring Using Factory Pull Switch

[John76]

Try this wiring schematic . Check your ground(s) and fuse(s).

This uses the standard push-pull switch that is the same as the rear window defroster switch.

 

BMW 2002 Fog Lights.pdf

[AustrianVespaGuy]

This comes up frequently so I'll link to my article for the full details.  But my advice for @achman would be as follows:

 - Wire the driving lights with a relay using the white/violet wire in the nose near the radiator from the high beams.  No switch necessary, relay just turns on the driving lights too whenever the high beams are on.

 - Wire the fog lights to your late-style foglight switch on the dash.  You will almost for sure need to pull new wires for this; I would recommend using the 4th factory relay slot if you have it available. You need to remove the instrument cluster from the dash to get to the switches, but then you can unscrew the knob and silver faceplate screw to remove the switch and get to all of the wiring.

Everything you ever wanted to know and more about 2002 lights here:

 

[Gr8WhtHype]

On 9/13/2018 at 10:51 PM, Simeon said:

Get a test light and start checking the wiring. 

 

Check for power at the relay via the battery feed and inline fuse using an independent independent ground for the test lamp (battery negative). If you have power then tick that off the list. 

 

Connect the test light to the battery positive positive and the check the ground wiring at the relay. Lamp lit shows that the ground is OK, no lamp then check the quality of the ground at the relay screw. 

 

Flick your switch and see if you get a click out of the relay. If it is clicking then move on to checking for voltage at the fog lights and then checking their ground out. If it doesn’t click then you need to check the switch circuit. It sounds like this has a supply from the fusebox that goes via the switch to the relay. Just check for voltage at all accessible points working from the fusebox connection, to the switch and from the switch to the relay and then the relay to ground. 

 

If that all checks out but the relay still isn’t working then try swapping the relay out or false feeding it directly from the battery to see if it works. I have found that my original round can horn relay can ‘freeze’ if not used for a while.  A smart tap with a screwdriver handle will get it working again followed by a few good horn blasts. Perhaps your relay is similarly effected?

 

I had power at the relay, but problems with the ground. I cleaned all points of contact on the relay with a wire brush and emery cloth which remedied that problem. They relay clicks when I toggle the fog lights, with the headlight switch disengaged or with the parking lights running. But once the head lights are engaged, I no longer hear the relay (not sure how relevant that is).

 

I have voltage at all fuses, including #9. I did not pull the dash to check the switch. How likely of a culprit is that given that it actuates the fog light relay?

 

I noticed that John76 recommended wiring the relay differently, which I may try. I saw another wiring guide was posted, which I have not read yet. I'd really like to understand this problem if possible before moving onto a different solution.

[John76]

Are you using the old/original Hella Round relay?  These have a different 4-pin configuration than the square-style Bosch relay in my diagram.

Hella relay: 30/51 is the +12V source,  87 is the load (lamps),  86 is the trigger source (+12V from fuse #9....when low beams are turned on),

and terminal 85 is to ground (thru the pull switch) to turn on/off the fog lights....only if the low beams are turned on.

 

John