01 Tahoe Fog Light Install Question

[huffster329]

I would first verify that the fog light relay is in the fusebox. If it isnt then acquire the correct relay. Put a meter on the normally open contact terminals in fusebox to see if one side is hot (12v). Test inside oem fog light switch to see if relay energizes relay and closes the contacts. If not then that will need to be corrected. COuld possibly be a PCM program issue. Ill have to check my schematics to verify that one.

This is the fuse box the way it was.


I added the relay. According to the diagram on the back of the fuse box cover, the 15 amp fuse to the left of the relay is for the fogs too (it was already in there.)


Installed the new switch.



I am getting power to the fuse and the lower left terminal where the relay goes.

 

[huffster329]

Test inside oem fog light switch to see if relay energizes relay and closes the contacts. If not then that will need to be corrected.

I'm assuming you meant "switch energizes relay." I still need to pull the switch back out and test there.

 

[rockola1971]

I'm assuming you meant "switch energizes relay." I still need to pull the switch back out and test there.

correct. Ill edit that so nobody gets confused 2 years from now when using this thread as a guide. Great pictures! Look under the fusebox and see if the normally open contact terminals are wired. Obviously the hot side is. See if you trace the opposite side of the normally open contact (That would be the output side leading to the fog lights). You might luck out and have most of the wiring already down in the area where the fog lights harness would connect to. GM likes to tuck shit in the loom at the factory when certain options arent installed.

 

[huffster329]

correct. Ill edit that so nobody gets confused 2 years from now when using this thread as a guide. Great pictures! Look under the fusebox and see if the normally open contact terminals are wired. Obviously the hot side is. See if you trace the opposite side of the normally open contact (That would be the output side leading to the fog lights). You might luck out and have most of the wiring already down in the area where the fog lights harness would connect to. GM likes to tuck shit in the loom at the factory when certain options arent installed.

I would be thrilled if most of the wiring is already there. I'll take a look at that and report back. Thanks for the help.

 

[05Single]

No you're right I shouldn't even have mentioned it.
In the end we know his heart is set on 100% oem which is great. Guess I was just trying to over help and went backwards with it lol that's my bad and I'll admit that.
I'm not a sparky like you but i know enough that I won't start my truck on fire, but then again I have to realize how experienced the other guy is asking too.

 

[ScottyBoy]

I added fogs to my 01. I searched high and low before I did it, and many many people were saying that the OEM switch send a quick pulse to the BCM (which is also how the switch tested when I metered it) and the BCM triggers the relay. To have it working on a truck that was not originally equipped with fogs, you supposedly need to have the BCM reprogrammed. Yet on a 03-06, it's plug and play on every truck, no program of the BCM needed? I tried over and over and I could not get the relay to trigger. I got about as far as you are now and that's when I gave up and used a rocker switch and a relay to wire up the fogs with my own homeade harness.

 

[huffster329]

I added fogs to my 01. I searched high and low before I did it, and many many people were saying that the OEM switch send a quick pulse to the BCM (which is also how the switch tested when I metered it) and the BCM triggers the relay. To have it working on a truck that was not originally equipped with fogs, you supposedly need to have the BCM reprogrammed. Yet on a 03-06, it's plug and play on every truck, no program of the BCM needed? I tried over and over and I could not get the relay to trigger. I got about as far as you are now and that's when I gave up and used a rocker switch and a relay to wire up the fogs with my own homeade harness.

How did you wire from the fuse box to the lights? Was there an existing wire tucked away that you could use?


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[ScottyBoy]

I wired my own relay, with a fused wire connected to one of the positive lugs on the fuse box. I grounded one terminal of the relay coil, and the other is fed with a positive from the rocker switch in the dash, which feeds off the ignition switch. So the IGN had to be on to turn the fogs on. Mounted the relay underneath the fuse box and ran my wiring down to the fog lights. I actually only ran the positive, I just grounded them on the radiator support.

 

[MikeW]

Ok electrical wizards - 02 Tahoe with factory fogs. Everything worked fine until I switched to LED bulbs in the fog lights. Now when you press the 'dome light switch' 4 x (to cut off headlights), fogs cut out now too (nice thing is when you push to turn them back on - fogs come back on too without having to push fog button). Anyone have this or have a solution? (Would like to re-aim headlights and fogs but cant get just fog lights illuminated by themselves). Thanks