Fog Light problem

[Liberty97045]

I have a 2007 GMC Sierra with a Duramax LBZ.

 

My fog lights will not come on with the push button.

 

I have checked all the relevant fuses.

 

I removed the under hood relay and jumped from 30 to 87 and both fog lights come on but the indicator on the button does not. 

 

One of the other terminals (85 or 86) has full voltage on it. The other has around 10 volts. I read that the BCM (body control module) supplies a ground to this relay.

 

Aside from replacing the BCM, does anyone have helpful advice?

 

Thanks in advance

 

 

[Ak_grown]

have you tried to swap with a known working relay? use a multimeter and test the fog light wire at the switch? orange wire at the switch  if i remember correctly

[Liberty97045]

I did swap relays and test the fog light relay with jumpers. 

 

The coil ground pin is at 10.5 v with lights off. Switch running lights or low beams on and it goes to 4v 

 

anyone have a schematic?

[Liberty97045]

I figured it out. The problem is apparently a common one with this switch used on 2003 - 2007 models. There is a plastic "spring" in switch that is supposed to push the button back out. I used the tip of a knife to pull the button out and then pressed it again and the fog lights worked normally.

 

I found this video on how to fix the switch and also found an after market switch at Walmart for $39.

 

Looks like replacing the switch might take an hour at most.