I noticed the other day that it seems like if I enter my 2004 Express 3500 via the side door, turn the ignition key and play the radio, and then exit via the driver's door the radio stays on. Is this normal? I replaced the battery not long ago. I wonder if this is why it went bad.

 

with the key off, the door switch should input to the bcm to power down the radio. the switch may not be signaling the bcm. easy to check the switch input with a scan tool.

 

Not ony that but your wipers would probably still have power too.

 

what type of scan tool were you referring to?

 

You will need one that reads body codes. Does the interior light go out when the door is closed?

 

Yes. Lights go out. I have a 2015 GMC Acadia. But the symptoms I have are the same. I read somewhere that it might be the drivers door switch. I am trying to confirm. I have an OBD II Compliant scanner tool. Are you referencing another type of scanner tool? If so, can you suggest a brand / model?

 

There are scanners, then there are scanners. Regular obd2 won't read (usually) transmission, ABS, or body control codes. I don't have anything brand wise I can recommend, but when you get up into total reading all codes, it can get $.