2005 Avalanche. It now has the air bag light on and the cargo light (light for in the bed) on. The cargo light is not on but the light in the cluster lights up and the button does not work. Also the dome lights work when the door opens but not if you push the button for the dome light itself. Checked out and the tcb2 fuse is blown, tried replacing and instantly blows the fuse. My Uncle has a Snap -on scanner and took a bunch of codes out of it but could not communicate to the brain itself since it blows the fuse even before you get it in all the way.

I think too much is going on at one time and all happened at one time to be all little problems. I think it might be the body control module at that rate. But don't really want to drop off to the dealer to get screwed.

Any suggestions?

 

Unplug the BCM harness and see if the fuse still blows. It's behind the driver's side knee panel.

Generally the module itself won't short out, it will probably be a wiring issue going out of the BCM to a controlled circuit (possibly shorted cargo light, dome light, glovebox light, etc.) Pretty much the best way is to get a wiring diagram and trace the power circuit for that fuse.

 

You need to get your hands on a wiring diagram to see what else is on the circuit. Then start unplugging one thing at a time until the short goes away, then trace out that circuit.

I had a similar problem to yours once, can't remember what year the truck was. But it was a short circuit inside one of the fog lamp bulbs causing that fuse to blow. Caused the cargo lamp to be inop, and caused an air bag warning light. Your problem could be anywhere.

 

thank you guys yes this is the hard part of finding a real schematic for the truck. Also yes un plug and diagnose what part is blowing the fuse.

 

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At $27, cheap for what you need, considering how deep you're going to be digging.

 

thank you, now i need is to download and find a huge chunk of time to diagnose.