Glad you saw this and bumped it. It seems you almost need to be an EE if you go with a custom alarm on the later MY RRCs as it seems almost every circuit is connected somehow.I just saw your post & had to reply. I have 95 Beluga Black LWB, in Lafayette but from Slidell. I have had very similar issues, maybe we could trade war stories, haha. After market Viper alarm seemed to be my problem. I absolutely love my baby but I have lost my mind a few times dealing with this truck. But I've also become a **** good mechanic, detective & investigator. I refuse to give in or give up.
I had a similar problem as the OP, but I had to resort to getting pro help in chasing down the electrical gremlin. Turns out we had a bad common ground behind the glove box. Once fixed, my lights were back to normal and the short was gone.
Curious if the OP ever resolved his issue?