Rear doors and hatch can't be locked or unlocked

[handmedownhoe]

I just picked up a 2005 Yukon Denali XL and after driving it home realized that the rear doors and hatch wouldn't lock with the fob or the door switches, only manually. Both front doors lock and unlock just fine but I'm not hearing any noise or movement coming from the rear locks. All of the actuators and wiring look to be in good shape from what i could see and so do my fuses and relays for the doors. Any suggestions on how i can fix this? I don't want to start purchasing unnecessary replacement parts if they're not needed.

 

[noodlesandsam2]

back 2 side doors, and hatch? For the side doors, I had the right rear that ( 01 1500 XL ) that stopped working at 30K miles. Never got it right. open one door, and see if they are connected correctly. not sure on the back. I never had trouble there

 

[Matthew Jeschke]

Welcome to the club! I have similar issues *sigh* Typically it's my driver door that will unlock but nothing else. Lock works fine. I swapped the drive actuator / latch with another from the junkyard. My locks worked for a while then went back to doing what they were doing before.

Few things I've tried so far:

- Wiggle wiring loom in door jam, as you try to lock and unlock door with fob. See if that helps. You can try other doors with similar method.

- Let truck set for 5 minutes or so... or disconnect battery and reconnect after a minute or so. This should reset the BCM to see if that is the issue.

- Wiggle wires to BCM... it has three connectors, immediately behind your knee bolster driver side. I believe it ties into the lock circuit. There's also a receiver for the fob. It's right hand side of cluster, immediately above and behind. You could tap on top of dash lightly, maybe a short there??

- What seems to work for me, every time, and I've no clue why... electrical panel driver side, remove the unlock and lock relays. Put them back in. Mine locks perfectly after that. I have no clue why... I've replaced both relays... same results. Maybe my issue is in that electrical junction block??

What I need to try but have been too lazy...

- Pull panel off one of the doors. Disconnect the lock connector. Probe it with a power probe (I LOVE MINE) or a multi meter. Test the actuator with power probe, then using fob check voltage from harness side when you press unlock. No voltage then you have a short in the harness. They tend to break in the door jam there. Repeat checking voltage while you press fob and wiggle wiring loom in door jam. That's where it tends to break.

 

[dps01]

Experienced an issue with my 2003 Z71 Tahoe when it was less than a year old. Front door locks worked correctly, but not rear hatch or rear doors (rear doors and hatch would actually lock, then immediately unlock while the front doors remained locked)

IIRC, the dealership found an issue with a loose ground and a crack in the fuse box housing…. Unfortunately that’s all I remember… it was repaired under warranty.