2004 Silverado Ext Cab. Trying to help a friend. Started with oil pressure gauge pinning on the high side. Then a/c and heater goes on and off intermittently ( he already replaced the control thinking that was the issue but it wasn’t). Then the battery went dead for no apparent reason ( it’s one year old). Then radio stopped working. He’s since found that whatever the issue, if he disconnects the battery the truck seems to reset itself. Up to now I thought it was a ground issue but after some research I’m leaning towards the BCM. Does anyone have any experience with these similar problems and did you try replacing the BCM ? Thanks for any help or suggestions.

 

Ok. Thanks

 

BCM is low on the list of suspects for me, I would look at the neg and pos battery cables for poor or intermittent connection. The cable can look perfectly fine but put a meter on it and it is high resistance or intermittent connectivity.