Hello, I am wanting to confirm with the community that my power door lock actuator is indeed broken on my 2000 Cherokee XJ. I had removed the whole driver's door wiring harness to re-solder broken wires in the door jamb, and had the passenger door apart to check for broken wires as well. This was all to fix my windows not working from besides the drivers control unit and the right rear not working entirely. My door locks all worked perfectly before diving into the project. I ended up figuring out through testing that my driver's window switch control unit was faulty (common lockout issues, switches not working even after re-solder), so I bought a replacement unit. Now that I put the driver's door harness back into the door and actually hooked up the connector to the lock module/actuator, the door does not lock and unlock with the rest of the doors. Holding the lock/unlock rod while triggering a door lock or unlock, I can feel vibrations like the actuator is trying to do something, but it never really moves. I also cut the connector off of a spare harness and hooked up + and - from a 12v 2a power source to the wires to attempt to manually trigger the actuator, with nothing really happening. All signs seem to suggest that somehow the actuator gave up, but wanted to double check, because it seems to be a costly replacement.

 

I've been there and done that. The power lock actuators are really frustrating. One of the few parts I have found on the XJ that is not serviceable. I was really frustrated with the actuators on my 98. One made noise like it was working but didn't actually move the actuator arm. I ended up getting a full set from a Grand Cherokee in a pullapart yard. I did have to modify the passenger one a little bit but it wasn't anything too difficult compared to pulling apart the door.
I have several spare ones that I keep meaning to cut apart to see what the heck is inside. If I am motivated, I'll cut one of the broken ones apart tomorrow. I have to imagine that it's a simple DC motor with some plastic gears. The plastic gears must wear and just not move anymore. I would guess it can't be too bad to cut it apart to fix the plastic gears and then glue it back together somehow. I have seen the prices for replaces and it's in the $40-50 per actuator range.

 

Nope, the XJ door actuators are pretty complex, way too much for a car, that's why there always problems with those, the best thing you can do is savaging some electric actuators fron any other car, all actuators are pretty much the same

 

Congratulations on actually thinking and testing something, instead of just throwing parts at it like most seem to do! It's really refreshing to see that.

I can only think of two other tests you could do before buying a new actuator:

1. Swap in a known working actuator from another door.
2. Look for something mechanical binding the lock rod. Maybe the actuator is trying to do its duty, but something is physically preventing it.