04 avalanche electric issues

[04avalanche2021]

I have a 2004 Chevy avalanche and having a bunch of electrical issues

doesn’t work :
Lock and unlock of fob
Front windows don’t work with either switch but the rear windows work with the rear switches
4x4
Radio
Obd2 scanner won’t work when you plug it in
Blower motor
4 gauges on dash stopped working
Battery light is on.
before all this used to shut off and torn back on sometimes when driving. Also over night my battery dies because my radio will turn on but light, just makes a bunch of noise

 

[Mooseman]

Welcome to the Nation.

Did you check all the fuses, including the mega fuse? How's the battery? Check its connections? After that, check the ignition switch or just replace it since it's a high failure rate part. Check all your ground points. Another possibility is the fuse box is corroded or has a broken trace under it.

 

[TollKeeper]

Dont forget, you have 2 fuse boxes, one under the hood, and one under the dash.

 

[04avalanche2021]

This truck doesn’t have a mega fuse, replaced battery, alternator, ignition switch, bcm out of a wrecked truck, redid the ground on the Frame under the drivers side floor, checked the connectors that go to the computer all seem okay

 

[TJBaker57]

With a replacement BCM from a wrecked truck even if everything else was OK the truck will not likely crank or start until a security relearn procedure is done.

 

[04avalanche2021]

Well I put one in it from another truck and it started right up

 

[04avalanche2021]

With a replacement BCM from a wrecked truck even if everything else was OK the truck will not likely crank or start until a security relearn procedure is done.

Well I put one in it from another truck and it started right up

 

[TJBaker57]

Typically the Passlock system has to do a relearn. A simplified explanation.... There's a sensor in the ignition lock cylinder with a resistance in it. The BCM security programming has to match this resistance value. There are many different values for this resistance but it is possible, although rare, that a swapped BCM just might have come from a vehicle with the same resistance value.