GM factory fog light switch

Has anybody used the factory fog light switch to run roofrack lights? I purchased the switch and once I realised it was a momentary switch, I knew it wouldn't be as easy as I thought. I have done a little research and there are a few videos out there on how to add headlights to other gm models, but I don't believe the h2 is prewired like they are. The harness to the switch is missing the 3 pins that operate the lights and will need to be added, but it looks like the spot in the fuse box for the relay is wired. I stopped by the gm shop today and I was told that there is no harness to be sold separately for the fog lights and that the bcm would need to be reprogrammed if it was added. I can seem to find anything that points me in the right direction.

I am thinking about just adding a latching switch relay directly behind the factory switch to run the lights, but just seeing if anyone knows of a correct way to do this.

Krackerzack said:

Has anybody used the factory fog light switch to run roofrack lights? I purchased the switch and once I realised it was a momentary switch, I knew it wouldn't be as easy as I thought. I have done a little research and there are a few videos out there on how to add headlights to other gm models, but I don't believe the h2 is prewired like they are. The harness to the switch is missing the 3 pins that operate the lights and will need to be added, but it looks like the spot in the fuse box for the relay is wired. I stopped by the gm shop today and I was told that there is no harness to be sold separately for the fog lights and that the bcm would need to be reprogrammed if it was added. I can seem to find anything that points me in the right direction.

I am thinking about just adding a latching switch relay directly behind the factory switch to run the lights, but just seeing if anyone knows of a correct way to do this.

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This is just my opinion, but were it me, I'd wire any extra lights separately, rather than trying to run them through existing switches or wiring. That way, you can run proper-gauge wire, heavy relays, and wire the whole thing directly to the battery instead of some dubious terminal on the fuse box. You can get switch gear that looks factory, but with specific labeling so you know what it does. Somewhere down my list of "stuff I need to do to the truck" is an item for adding lights to the roof rack I haven't bought yet. When I do that, I'll put the switches for those up on the ceiling console, and I'll buy them with specific labels e.g. "Side Lights", "Flood Lights", "Spot Lights", "Sasquatch Lights" etc.

It actually looks like it will be a lot simpler than I thought. I walked through our local junkyard yesterday (i think I enjoyed myself a little more than I should have), and looked at several GM and Chevy models. I was able to get an HVAC unit out of an Envoy and I also noticed that the glove box on the Silverado is the same box on the H2 (finding the color is the problem). While looking for the HVAC, I noticed that several vehicles of both Chevy and GM share the rear wiper switch with the foglight switch that the H2 uses. The wiring harness is already there for the bumper foglights on the trucks. There is actually an empty relay space in the h2 fuse box that is marked for "foglights". The switch inside the truck is only 3 wires, so that would just require running one wire to the hood fuse box (relay). Doing it like that would probably allow me to bypass the BCM which would allow the lights to be activated when the truck is off. I spoke to the yard boss and he said I could come out next week and take the time to trace out the lines and pull the harness if I wished. All the wires look to be wrapped together, so might be more work than I am willling to put it. I am going to take a look at it and if I can tell what wire runs to the BCM, I may try to pull or build a harness myself and have GM reprogram the BCM.

I have searched everywhere for this! Did you have any luck bypassing the BCM and wiring the factory foglight switch? If you did, please provide some detailed instructions. I can really use a manual on this. Thank you kindly.

This has been a straightforward explanation that I found so far... I have also purchased LED fog lights and will get the RY601 relay plus a diode and see how this works out. Keep in mind that this turns the fog lights into DRL. I am ok with that, as don't need a switch to operate them (the fog lights come on automatically)