I have a strange issue with the rear drivers and passenger side door locks.

Symptoms:
- can’t lock/unlock both back doors with fob or door buttons.
- lock relay gets hot and ultimately drains my battery in a couple days.
- when I plug the relay in, I hear it click and both rear doors lock.
- front doors and rear gate lock/unlock without issue.

Repairs so far:
- replaced both actuators
- replaced the lock and unlock relays
- took apart and cleaned/inspected both front door switches.

Diagnosis attempts:
- disconnected both back door actuators as well as the rear gate actuator and relay still clicks when plugged in and gets hot.


I’m not sure where to go from here. Any ideas? Could it be a problem at the fuse box?

 

You need the wiring diagram to properly follow and diagnose and test the circuits. Something is actuating the relay.

 

Most of the time this is due to a bad connection or a failing ignition. If this is occurring with the locks as well as a power loss then you may have a bad ignition switch. It can also be a fuse box or battery issue so it should be checked first prior to replacing anything.

 

Thanks for the replies. Looks like it’s a BCM issue after getting ahold of a wiring diagram and doing more testing.

 

I'm just an amateur, and frankly don't know where these lock and unlock relays are. At first I was thinking a bad relay, but you said you replaced both of them. Sounds like something, perhaps a switch, is shorting out and maintaining voltage on the relay. You said you cleaned and inspected the switches. Do you mean a visual inspection of the switches? I don't think you can tell if a switch is bad just by visual inspection unless it is obviously burned up or something. Can you get a voltmeter on the switch and verify that it is not shorted or providing voltage to the switched side (ie the relay) once the switch is released?