HeadnSouth

Thanks for your reply. I'll look at what you mentioned and come to think of it. It does have an after market radio and I did install a tailgate lock. The TL being the newest addition. I'll start there.

Thanks, I'll dig into it. I'm hoping it'll be easy.

Disconnecting the battery doesn't solve the issue. Besides I like to have a ready to go backup vehicle just in case one of my others decides to crap the bed.

2003 GMC Sierra I recently replaced my blower motor resistor and HVAC control module. I don't drive it much except for towing. Towing season is over and the truck will just sit. It doesn't more than a couple of days and the battery will dead. Battery is new, alternator charges fine. A buddy suggested removing the NEG terminal and attach a test light to the battery post. The test light is lit so I started pulling fuses and relays but the test light stays on. On top of that I have no climate control whatsoever. Everything else is stock besides some LED lights that are switched independently. Any suggestions on what else to look for?