 New LED headlight bulbs, now no fog lights, H4 style LED bulbs used |
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| barefoot |
 Jan 21 2020, 08:53 AM
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#1
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Senior Member  Group: Members Posts: 1,370 Joined: 19-March 13 From: Charleston SC Member No.: 15,673 Region Association: South East States 
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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 ?? |
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| theer |
Jan 21 2020, 01:37 PM
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#2
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Senior Member Group: Members Posts: 691 Joined: 31-July 15 From: Dover, MA Member No.: 19,014 Region Association: North East States
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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. |
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| lierofox |
Jan 21 2020, 03:16 PM
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#3
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Member Group: Members Posts: 256 Joined: 23-June 15 From: Paso Robles, CA Member No.: 18,880 Region Association: Southern California
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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. (IMG:http://www.914world.com/bbs2/uploads_offsite/i.imgur.com-18880-1579641506.1.jpg) |
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| Chi-town |
Jan 21 2020, 03:29 PM
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#4
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Senior Member Group: Members Posts: 851 Joined: 31-August 18 From: Disneyland Member No.: 22,446 Region Association: Southern California |
Cut the white/blue wire and ground it
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| burton73 |
Jan 21 2020, 03:58 PM
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#5
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Senior member, and old dude Group: Members Posts: 3,823 Joined: 2-January 07 From: Los Angeles Member No.: 7,414 Region Association: Southern California
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LEDs on #41 at PMB
Bob B  |
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