Hello people. I am very new to this site (as well as to diesels and working on cars in general), but I've found a good spot here as I have already learned tons about these great cars from all y'all's posts!

I bought my -81 300sd 5 months ago and until tonight, the door locks have been working flawlessly. Tonight, the locks started doing a weird thing: they started cycling on their own between lock and unlock (except for the driver's lock). What I mean by this is that it is as if there was somebody standing outside the driver's side door and turning the key back and forth in the lock. I didn't ever get to fully diagnose this because the car seemingly stopped doing it but I am assuming that this would go on until the vacuum reservoir is empty (and if it is due to electronics, it would still go on until my battery is drained, right?) Has anybody ever experienced this kind of errant locking, and if so, what was the cure? Where should I start - the driver's door or the trunk? I've searched for a post similar to mine, but wasn't able to find one. Thanks in advance.

Lubricate all latches, locks and remove door panels to lube the internal linkage + pivot points.

The basic problem = mechanical jam in half way position.

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1985 300SD
1983 300D
2003 Volvo V70

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