On my 2003 Monte Carlo the battery would go dead after sitting a while from a parasitic drain from the battery.
I took the whole wire harness out of the engine bay, and ? attempted to take the whole wire harness out from the dash, thought twice about that.
Only to fish for the short or break in the wire harness.
Come to find out ?
It was the Body Control Moduel.
The Body Control Moduel had grimlins in it.
It caused a parasitic draw when it decided to work or come online, and when power was applied ? It intermittently didn’t want to come online when the power was applied.
I didn’t have the money to buy a new one and have the dealership reprogram one.
So ? I made a separate switch and fuse for the BCM and instrument cluster and when ever I had problems it not coming alive, or coming online when you applied power to the BCM ?
I would just toggle the switch until the BCM decided to come online.