1985 w126 300sd cental locking system failure to lock
I have posted this question on a few other Mercedes Forums with no assistance. So...I have paid the 30 bucks for hopefully some light to be shed.
I have a strange problem with my central locks.
The problem I am having is that locking any controlling (driver passenger trunk)lock will cause all locks to unlock but it is impossible to lock the doors. I obviously have no leaks.
What I have so far.
I have run the pump on the bench and if I ground any of the 3 pins the pump pulls untill the vac switch makes. Then if I apply 12v to a pin the pump pushes until the press switch makes. This seems to make sense. Keep in mind I did not test the pump with a constant 12v on any pins and I will try that later today.
I also tested the wiring in the car and all is correct.
