2005 Vito Electric Window/Lock Actuator/Door Module fault?

[Squibby17]

Hi all,

An an ex-Sprinter owner who's had zero issues with the van for over 14 years, I'm 6 months into owning a Vito that's driving me up the wall, and I'm reaching out for any advice:

Back before Christmas, while putting the passenger (NSF) electric window down, there was an audible pop from inside the passenger door and the window stopped working. Within another day. the central locking stopped working on that door. Initially it would only unlock and not lock again, but shortly afterwards the whole central locking system for the van then packed in with an intermittent red light on the locking switch on the dash. Occasionally the C/L would come back to life and allow me to lock the van, but then stopped again.

I've taken the door card off, and there's a 12v supply getting to the module in the door. Popping the cover off the module shows no visible damage/scorching on that board, however if I unplugged the lock actuator on that door the central locking on the rest of the van came back to life. However putting the window down results in a short 'squeaking' noise coming from the module with no window movement. If the 2x power wires in the plug to the window motor is connected to a 12v supply, the window goes up and down with no issues. To rule out issues with a limit switch on the window preventing the window being opened, I left the window halfway up and reconnected the module. Again, no movement using the switch on either driver or passenger doors to get the window up or down. When it's run by connecting the 12v supply directly to the motor it glides up and down without issue.

My best guess was that the door control module was faulty, given that both the locking actuator and window had both developed faults at the same time, however a replacement module hasn't made any difference. The new module doesn't seem to cause any overall issue to the rest of the central locking system when the locking actuator is reconnected unlike the original module.

I don't have access to any diagnostics tools for this van, however it appears from the wiring that there's both canbus and logic to the module, but I can't find any info online to help narrow down the fault. I'm struggling to believe there's so many faults common to systems run from one module that aren't related to a faulty control module, and all have broken around the same time by coincidence.

Grateful of any help/wiring diagrams/tips on trying to fault find and narrow down where the issue is.

 

[Squibby17]

Hi all,

So, update after the van has been via two garages - there's a permanent fault showing that Terminal 30 is over voltage, and it appears that the replacement door control module has also now failed. Even with just the lock actuator plugged in to the replacement module, that's enough to take down the entire central locking system on the van (absolutely fine though without the actuator).

It's due to be looked at by a Mercedes specialist auto electrician - just wondered if anyone else had experienced "over voltage" faults on a 12v supply to a 12v module, and what the possible causes/prognosis could be?

Thanks