Ok well there is this Ebay auction where this guy is selling the harness for stock fog lights for a Chevy silverado but I have a GMC and I was wondering if they would be compatible with my GMC since the actual fog light is diffrent between GMC and Chevy?

Here is the link

 

It should work. I don't see any reason why it would be different between GMC and Chevy. The fog light is different, but the plug connector should be the same.

 

I have the Denali front end conversion on my Sierra and I bought a Silverado fog light wiring harness and it all hooks up fine. As snakeoiler said, the fog light is different but the male/female connectors on the fog light and wire harness are the same. Don't forget the relay and fog light button switch too, it's shown in the picture of that ebay auction.

 

Its strange because I emailed the seller and asked him if the harness was the same for GMC and Chevy and he said no.

 

I bought that same kit for my brother's HD. He is a great seller and I am sure it will fit just fine.