vladichik

Hello Everyone,

I just purchased a new to me 2002 G500, I was so excited about purchasing the car I did not check the central locking system. As I was getting ready for my first weekend adventure, I discovered that my locks don't work on the front two doors. The locking system works on the rear doors and the hatch as they should with the button inside the car and the key however the front doors do work react to either the key or the button inside. If you manually lock the drivers and passenger doors, they stay locked.

Here is whats been done so far:

- I checked the fuses in all 3 fuse panels (all fuses are good)
- Took apart a rear door to measure voltage on actuation within the connector for the door lock actuator, it reads 12v to either pin when actuating via button or key
- Took apart the drivers door and removed the door lock actuator to check its functionality
- I checked the actuator from the front door on the rear door and the actuator is working fine
- When I checked voltage at the connector on a front door It seems that one of the pins for the door lock actuator is showing a constant 3.00V
- When using the button or key the voltage does not change at the connector

I connected an old AutoBoss scanner to the car and communicated with the door module on the drivers side. The scanner shows that door control module receives the signal to lock and unlock the door yet theirs no voltage change on both the passenger and drivers side.

Does anyone have any ideas on what this could be?

vladichik

rickdo13

I am having the same problem. What fuses did you specifically look at ? I’m not sure which ones to change

PeriodCorrect

Did you try chaining the actuators, Rick? They're $30 off eBay. I just purchased one to replace a faulty rear passenger side door lock. I will report back on its' success/failure once it arrives.

rickdo13

I did change the actuator and it still doesn’t work. That’s why I’m assuming it may be a fuse or control module. What fuse did you look at to change?

PeriodCorrect

Unfortunately, that's where my technical knowledge/troubleshooting ends. Have you checked on ClubG or the G centered facebook groups? Does the owners manual state which fuses are responsible for the door locks?

If replacing my actuator doesn't do the trick and I have to chase the fix, I'll be sure to let you know what myself (or my mechanic friend) find.

rickdo13

Thanks for the help. Yeah I will continue to try and find a Solution

PeriodCorrect

Lmk if this helps:

https://fuse-box.info/mercedes-benz/mercedes-benz-g-class-w463-fuses-and-relay/amp#Fuse_box_diagram

paulunm

I don't know the 2002+ trucks very well, but if you have a Keikert relay- I'd change that out with new one.

vladichik

Hello All,

It's interesting that this thread is finally getting some reply (almost 4 years later). I was able to figure out this issue on my own by testing the individual components. The module in the rear doors is prone to water intrusion and corroded from the inside. Replacing both rear door modules resolves the issue, they cost roughly $300 each from the dealer. I am sure you can find them used and in good condition from the secondary market.

Thanks

PeriodCorrect

What module is it? Do you still have the truck? How has it been?

vladichik

Door control module, when you take your upholstery off the door it's located next to the speaker.
Yes, have one sold the other one. All is fine with the module.

YCHU

Check fuse number 8 under center console which is for alarm siren.
For my 2004, the culprit was the alarm siren near front grille which caused the #8 fuse to burn, and the remote control didn't work.

jfrankha11

BIG QUESTION: SNCE THE DEALER SAID MY AAM is not communicating and they can not replace it (obsolete), can I replace all my computers with a used set from another car including the key, will that work since everything is synchronized/proprietary. No one in the Dallas area has any good news for me about the 2004 ML350 being able to be repaired. Does anyone have any suggestions, good interior, body, paint, new tires, good engine/tranny but I can't start it or go anywhere?