Fog light fuse keeps blowing :(

[SeatownE30]

Hey guys! I need some help..

I recently purchased a 91 318i with the passenger side fog light out. After doing some research, found that one of the two fuses were blown. So i replaced the fuse, checked the lights and it worked! Simple enough right? Well...

So this past weekend i noticed that that same fog light was out again with a blown fuse. Performed the same procedure and it blew again. Even went up to a 10amp fuse instead of 7.5.

Any ideas what might be doing this? Thanks in advance!

[russhixmo]

Check the wire rite behind the headlight where it passes down to the valance from the motor bay, they tend to rub and fray possibly causing a short

[SeatownE30]

Okay, i'll give that a shot. Thanks! I noticed the fuse blew when i revved the motor from a stop light. I dont know if that's helpful at all, just noticed it.

[SeatownE30]

So i tried what russhixmo said and no luck. All the wires behind the pass headlight look good. Does anyone else have any suggestions? Its so strange how the foglight works initially until i turn on the car or rev the motor, then the fuse trips.

[Ceeker]

a possible ground short somewhere is causing a surge in power to the lights making the weakest link (fuse) blow. what watt bulb are you using in the fogs? a higher watt will draw more power putting demand on the system. I believe 10amp fuses are for the fogs. You "[B]might" want to put 15amp in to see if it blows those. it may not but keep your eyes on the wires to see if they get hot. If I recall I think I did the same because for some odd reason my 318is was doing that as well. I never had problems with it afterward. I was running 100watt in my fogs and I threw 15amp fuses in.

[russhixmo]

Creeker mite be on to something, if there not OEM fog lights or bulbs they may draw more power or ur pushing to much power to them and the bulb mite be strong and pop the fuse instead of the bulb. Its happened to me before, also try the 15 amp fuse and see if that helps but be careful not to melt any wires.

[SeatownE30]

Thanks so much Ceeker and Russhixmo! To be honest, i never thought of putting in a higher fuse in fear of melting wires but i gave it a shot last night and drove it early this morning while it was still dark and the damn thing worked! The fuse didn't trip! :)

As for the bulbs, i'm running the PIAA H3 Ion Crystal (yellow) bulbs that are rated at 12V-H3 55=85 watt: providing 85 watts of light using 55 watts of power. Didn't want to go too high in wattage but love these bulbs. I've had these same bulbs in 3 cars already. :)

Anyways, thanks again, i'll keep an eye on the wires and hopefully that'll be it for this issue.