VX Spontaneously Unlocking

[Jason Patterson]

I have a 2001 VX S which has started to spontaneously unlock. When I lock it everything seems to lock just fine, then some time later it will suddenly unlock all of the doors. Sometimes this happens in mere seconds but often it doesn't happen for hours, and sometimes not at all.

It seemed to start after going through a car wash, so I suspect it's water related. The same problem also happened for a couple of days a few years ago, then went away. Back then it was also water related - very high humidity in that case.

Am I looking at a door actuator failing here? If so, why does the car unlock all 4 doors in response? I've removed the cover from the door which I suspect got the most water in the car wash, but I can't see anything obviously wrong and the actuator doesn't seem to be struggling to move the lock or anything.

Or is this a BCM water issue? Or maybe a grounding issue of some kind?

It feels like the car is detecting what it believes is some kind of fault and deliberately opening the doors in response.

Needless to say, it's quite disconcerting to lock your car, walk away, and return hours later to find it unlocked!

Any ideas?

[mrbeef]

what if you deadlock the doors? does it still open?

[Tromac]

Do all of your locks operate properly?

I have to repair the wiring in my rear left door for the same reason. What is happening in my situation is that the power to the actuator keeps getting cut, and so when I central lock the doors sometimes the tab remains up. As a result the car thinks that someone has manually pulled the tab from inside the car and the computer responds by unlocking the rest of the doors.

My temporary solution is to manually lock that door, and every time I lock the car ensure that the problem lock remains in a locked state. If you are having the same problem then do not dead lock your car, because it may take a very long time before you get that door open again otherwise (the door will be permanantly deadlocked until (if) the actuator ever gets power again).

[Jason Patterson]

Problem solved. It was a grounding issue of some kind. I followed the advice given at VT Body Control Module - HSV Forum to clean all of the grounding points inside the engine bay, and sure enough the problem is gone. It's been 10 days now, so I'm confident it's solved. I assume the BCM must have been detecting a minor grounding issue and unlocking the doors as some kind of safety measure. The HSV forum says this is common after steam cleaning the engine bay. I guess in my case the car wash was a close enough approximation to steam cleaning!

PS: Tromac, your problem doesn't sound quite the same as mine was. It sounds like yours really is a failing actuator, or the wiring/connection to one anyway. That problem should be immediate - either the door locks or it doesn't, but it won't lock and then hours later unlock spontaneously, right? It sounds like you're on the right path with yours. Good luck!