Can anyone lend some advice as to why my central locking system stopped working? When I lock the driver's door with my key the rear door lock wiggles a bit but doesn't move up and down. I can't see the others well enough to know if they wiggle- but they definitely don't lock/unlock. I think I know they are vaccuum powered and probably electrically actuated but where is the diaphragm? Thanks in advance!
The way to trace the leak is to isolate each actuator one at a time until the system works and then you have found the source.
Under the carpet in each foot well is a black plastic cover and under it runs the vacuum lines. If you find where the line branches off to the door, there shoule be a rubber junction peice where you can disconnect the line going up to the door and blank the rubber junction off with something like a golf T.
I would do the fronts first, because they are the easiest carpets to pull up.
I would then do the trunk and fuel flap, because you should be able to isolate them near the pump itself situated under the back seat (it's surrounded by grey foam).
Careful, though. If there's a leak, the pump will not stop working after you lock and/or unlock the door, and will burn up. Chances are one or more actuators are stuck or dirty. As far as I know, there are six (seven?) of them, four for the doors, one for the trunk and one for the gas flap (and probably an additional one for the glove compartment - I'm not sure about this one, my 124 didn't have that.)
I want badly to rule out a general failure somewhere before I disasseble my doors...I believe I will start my investigation at the pump itself. Thank you all so much for the insight!
Thanks for all the guidance. I inspected my pump (under the back seat). It was inop. I exposed the curcuit board within the pump assembly and put power directly to the pump wires and got only sparks. I also applied suction to the vaccuum lines and found that all of my doors locked and retained the vaccuum pressure. Be careful with this maneuver though as it locks the fuel door and it must then be manually unlocked via the trunk!
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