Hey there!

Did a good deal of research in the forums and can't seem to find something that fits my situation. The drivers side, rear passenger door lock doesn't work with buttons on door or remote. I can physically lock and unlock the door with the pogo lock. I've had this issue with other vehicles and it is typically the actuator (as mentioned on several other posts). However, what strikes me as odd is that I don't hear or feel anything in the passenger door attempting to lock or unlock the door. I hear the actuator in all the other doors.

Thoughts?

Thanks...Peace...Away...

 

Did you ever find the root cause? I have this issue and have just replaced the actuator with a new MB part.

 

Honestly, I just adapted to it. I am planning to sell it soon, maybe to a good friend. If I end up selling it to my friend, I feel more compelled to fix it than if selling to a stranger. Did you do the replacement yourself or have it done at a shop? Are you willing to share your total cost for the project?

Thanks...Peace...Away...

 

I did the replacement myself. Bought part from autohausaz.com
Actuator assemblies are about $325 each. Prices vary depending on door location and if you have keyless-go.
BTW, there is an alternative to going around to the other side of the car to unlock the door. If you press and hold the unlock button on the fob, all the windows will start to open (including sunroof). This is a great way to let the hot air out of the car on a sunny day but also gives you access to the rear door lock button. I wouldn't recommend this as a long term solution since it will drain the key fob battery after a while.

 

Yah. Thought about tackling it myself last time also. Have the tools...not sure I have the time :-)

 

Quick follow-up as I try to determine my next step...

Did your actuator/door make 'any' noise at all when you tried to unlock? Did you 'feel' any activity in the door when you tried to unlock?

Thanks...Away...

 

I don't think I heard anything from my original actuator. Probably because the door panel was still on. I have the new actuator in place without the door panel on and it seems to make a slight sound when I attempt to actuate the lock. I will be going to my Merc mechanic next week so he can check the front SAM which controls only that door.

 

This seems to imply that you still have the issue even after replacing the actuator. Am I correct here?

 

I still have the issue after replacing the actuator 2 times. I then brought the car to my local independent shop. He scanned the front a rear SAMs, no errors. I then bought a $10 test probe from Harbor Freight that detects "no signal", +12v and Ground. It has a single LED that is off when no signal is present. Lights up Red when 12V is present and lights up Green when ground is present. I found on a different thread that the Violet/Black and the White wires are what controls the door actuator between the front SAM and the left rear door actuator. With the door panel removed I was able to pierce the wires with the probe and actuate the lock/unlock button. I tested this on both the Violet/Black and on the white wire. Each time the lock/unlock was pressed I got a one second pulse but it was always ground. I never got a +12v signal from either wire with either lock or unlock. I believe my SAM is bad. It is just a PITA to get to and $$$ to replace and then reprogram.
You may be able to access the wires without taking the door panel off if you separate the boot where the wires pass by the door hinge.
Here is the tool that I used:https://www.harborfreight.com/comput...obe-63597.html
I made up a cable extension for the probe that plugs into the rear cigarette lighter socket for convenience.
It is still a 2 person job since there is no lock/unlock button in the rear. I suppose you could use the key fob but you still need 2 hands to hold the probe to the wire.