83 SD passanger locks funky...

[vstech]

yup, funky. best way I can describe it.
for those not familiar with the SD locking system, it's electric pump actuated, not engine vacuum...
the back door will lock and unlock randomly...
some days it locks fine.
some days both the front and rear will lock and unlock on their own.
some days the rear lock only is affected. sometimes it will act like it's gonna lock for a while, then just not lock.
whatcha all guru's of the tri star think?

[tr1cky]

Originally Posted by vstech

yup, funky. best way I can describe it.
for those not familiar with the SD locking system, it's electric pump actuated, not engine vacuum...
the back door will lock and unlock randomly...
some days it locks fine.
some days both the front and rear will lock and unlock on their own.
some days the rear lock only is affected. sometimes it will act like it's gonna lock for a while, then just not lock.
whatcha all guru's of the tri star think?

I recently replaced one of these pumps located in the trunk near the spare. Similar issues before the pump failed, may or may not be the same issue as yours.

[Phil]

If it's doing that on it's own then something has to be activating the pump so I would guess an electrical short and the most likely location for it would be at the drivers door hinge area. The wires are now 27 years old and can bend back and forth just so many times before they start to break and possibly short to each other or ground. I had to go through mine and splice in new sections of wire at that point for almost all seat and lock functions.
Look at post #13 on the attached for a description of the system.
Door locks 1982 300SD W126

[tbomachines]

I would guess the switch at the door as well. Can you hear the pump activating at all?

[vstech]

nope switch nor pump activating. and its just the passengers side.