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914World.com _ 914World Garage _ New LED headlight bulbs, now no fog lights

Posted by: barefoot Jan 21 2020, 08:53 AM

Just installed H4 base LED headlight bulbs, now fog lights don't come on, but headlights get a tiny bit brighter. I guess I'll have to do the foglight wiring switch mod to by-pass the headlight switch, was hoping not to have to do this mod.

Anyone else bump into this problem ??

Posted by: theer Jan 21 2020, 01:37 PM

Yep - a common problem with the LED headlights messing with the fogs Try the fogs with high and then low beam. You get some strange behaviors.

The fix is to move the fog light ground from the high beam circuit directly to chassis ground.

There was a thread recently (late last year?) that dealt with exactly this issue.

Posted by: lierofox Jan 21 2020, 03:16 PM

Yeah, the problem is that in the stock configuration, the coil for the relay that controls the fog lights is grounded through the headlight high beam filament. When you replace the headlight with an LED, that no longer becomes possible.

Like Theer said though, the simple fix is to just move the ground wire for the relay from the back of the fuse panel (Fuse 1, it's a white/blue wire that tees off from the wire that goes up to the high beam indicator in the gauge cluster) to any available nearby body ground.

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Posted by: Chi-town Jan 21 2020, 03:29 PM

Cut the white/blue wire and ground it

Posted by: burton73 Jan 21 2020, 03:58 PM

LEDs on #41 at PMB

Bob B
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