I think I have a problem with my BCM - I've had all the windows go down on their own a couple of times, and the door lock horn beep no longer works, which is kind of a blessing. I've installed DRL's and a trailer wiring setup, both have inline fused power leads that attach to the battery terminals. The trailer wiring has a module that runs the separate brake and turn signals, and has a connector that plugs into the factory harness next to the drivers side tail light. (No cutting)

I've read about service departments refusing to work on cars that had aftermarket alarms installed, which is reasonable because any I've seen had a LOT of splices. Probably applies to remote starters too. In my case, both were simple plug ins, and have been working fine for a few months, the BCM thing is recent. I've also pulled both fuses with no change.

I know each service department is different, but has anyone experienced warranty refusals because of non factory accessories? I suppose I could pull everything out, but the heavy 12GA power wire for the trailer module runs right by the BCM in the passenger footwell where the tech would see it. It was a serious pain to get it in and through the rubber cap on the windshield cowl, I really don't want to do that again.