I have a problem with my vacuum door locks on my 300TD wagon. The door locks will lock most of the time if I lock the door within 2 minutes of turning the engine off. There are times when 3 of the 4 doors will lock but not the rear hatch. At other times all the doors (including the hatch) will not lock. Normally I have to start the engine and let it run for 5 minutes for the doors to unlock.

I checked the vacuum from the pump and I am getting 17 inches of vacuum. I replaced the 3 way vacuum valve on the driver's door. I disconnected the large vacuum line from the brake booster, plugged the line, started the engine, but no change in the door locks. All of the vacuum lines and vacuum tees under the hood and along the floor have been checked and no problems.

Any suggestions? Thanks.e