The locks on my 97S320 lock and unlock on their own once I put the car in drive. The most irritating thing is if I press the lock button one way, the system does the opposite. The scariest thing is closing the drivers door knowing it might lock...Any suggestion?? Is it a bad pump or crossed wires?

 

Only when the car is parked on the drive?

 

Maybe its crossed wired...

 

it happens in park and drive. I dont know if its crossed wired bcz it just started happening. I nstalled the pump in almost a year ago.

 

Hi,
Sorry. I misread your post.
I thought you had said....Only when the car is parked ON the drive? Not IN drive.
Initial thoughts are that the PSE or CAN are causing the problem.

Need to understand a little moreabout EXACTLY when this problem happens.

The PSE is the "pump" in the boot but this module also carries a number of other functions. It also communicates with other modules in the car via a digital highway known as CAN.
If there is a "short" on this CAN lots of strange things can happen. Hypothethical example. The turn indicators can operate when you press the brake.
The short is usually due to the RESIDUE (corrosion products) of water (moisture) between the two wires that make up the CAN.

When EXACTLY do the locks activate?
When you press the brake pedal prior tp moving into drive or when you move into drive or shortly afterwards i.e. 2 mph etc.
These 3 conditions point to totally different scenarios.
Do you have a bulb failure light showing, does your interior light work correctly. Does the Alarm work correctly? (Lock car with remote (activate alarm) with window down and then open vehicle thru window)

Stuart

 

The pump that controls the headrest, lumbar system, and door locks. After I put the car in drive the locks lock and unlock once the car is in motion.When I come to a stop they will pop up. If I lock the doors again, with in 20 seconds it pops unlocked.

I don't have any bulb light failures, I interior lights work fine, the alarm works correctly. I cant understand it....thanks for any insight you can give me.

 

My 2001 ML 430 is doing the same thing. Mine happens when I first step on the gas. If I am at a light, as soon as I step on the gas my doors lock and unlock by themselves. My locks are not arming correctly either. GRRR!!

 

hello,

first what you do is , take the rear seat off to get access to the pump, unplug all electrical conections, after start taking the vaccum hoses ( unplug them une by one) like for exampe unplug the first wait 5 seconds and plug back in, unplug the second line and wait 5 seconds and plug back in, do this to all the vacuum line plastic hoses so you dont cross them and lose track of the order, after you've done this put everything back together, electrical connections and seat, pump the trunk so you get access to the fuse box find the right fuses for teh central lock system i think are 2 of those if i recall it right, take the fuse off wait 5-10 minutes put the fuse back in , after take teh key and lock and unlock the driver side door 3 times, jump in the car after you've done that and take it for a ride, see if it still does the same thing again.. let us know how you do on that..

good luck

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