Fog light issue on 87 325is

[Ceeker]

Hey gang,

Wondering if you can help. I recently bought an IS with the factory spoiler and fogs. My left side fog light isn't working.

I have replaced the bulb on the left and swapped it into the right just to make sure my bulb and ground on the body of the lamp wasn't bad.

Fuse box: I tested the 7.5 amp fuse to make sure it was good. I have power using a test light to the right fuse but a weak light coming from the left side fuse. the light is very dim. So this tells me it's getting power. but for some reason no fog light.

What could be the issue?

thanks.

[Northern]

Check for power/ground at the plug and work your way to the ground or fuse, whichever isnt working. Could also be a dirty contact or corrosion in the fusebox.

[bmwguy325is]

The ground wires like to corrode. You may want to check beheind the light and up all the way behind the bumper. I got so sick of mine they got yanked. more so cause its hard to find lenses and they crack sooooooooo easy.

[Ceeker]

UPDATE: well I have power to both left and right fog fuses and checked the ground from the light side with a test light to a power source and it's good. But when I tested the power from the light to ground I got nothing. So it leads me to believe I am not getting power to the left fog light.

would it be ok to to run a new power wire from the right side to the left to bridge the two rather then trying to trace the problem?

[bmwguy325is]

Ya Id say new wire. Thats the point I got to and said eeef it and Bought new lights a crispy new wire loom.

[Ceeker]

By running both lights through one fuse you will be increasing current flow which might require bigger fuse and wire supplying current to fuse. Depends on combined wattage of circuit. You will still have a possibly broken wire for the left light circuit that will still be hot when you turn on fogs. If you do decide to use the right for both you should pull the fuse for the left side unless it is shared. On the chart it looks like it only supplies the fog.

well, out of curiosity I decided I would try to trace the wires back from the fog light. Since I have the early style IS spoiler I didn't feel like removing everything so I slipped my hand through the inner headlight cover and found the female jammed between something. I dislodged it and then looked for the male side which btw wasn't anywhere - evidently NOT connected hence no power to the fog. I found what I suspected to be it. two pins and the colors seemed the same from the fuse block. threw the test light on and then the fog switch. the circuit got power so I knew this to be the lost wire. I stuck the pins into the female plug and threw on the fogs and sure enough. Left side lit up.
I went to my donor car and cut the male plug side off and connected it to the female of my car. Almost factory fix!! problem solved.

[PNWDan]

well, out of curiosity I decided I would try to trace the wires back from the fog light. Since I have the early style IS spoiler I didn't feel like removing everything so I slipped my hand through the inner headlight cover and found the female jammed between something. I dislodged it and then looked for the male side which btw wasn't anywhere - evidently NOT connected hence no power to the fog. I found what I suspected to be it. two pins and the colors seemed the same from the fuse block. threw the test light on and then the fog switch. the circuit got power so I knew this to be the lost wire. I stuck the pins into the female plug and threw on the fogs and sure enough. Left side lit up.
I went to my donor car and cut the male plug side off and connected it to the female of my car. Almost factory fix!! problem solved.

Every time I touch mine, the pin comes out of the socket. Common on these I suspect.

[Ceeker]

the pins have an anchor that when it slides into the socket it grips the housing. Hence the name- push pin. :-) If they get corroded that may break and make the pin loose. I'd just find a donor car and cut and solder a new socket in. Works like a charm. just make sure the donor pins aren't corroded.