I’m guessing some spliced in either a remote start or a fob into the factory system. You need to find a wiring diagram to proceed And cut that junk out. Based on the wiring workmanship, the lock Issues aren’t surprising

Be careful what you are doing, it’s easy to brick a 1999- on Volvo

That action, locking followed by unlocking is normal function for the Volvo locking system if it detects a door ajar. It could just be one of the lock signals isn’t getting to the lock control module I though the driver door key opens the driver door mechanically, so if that isn’t working, you need ...

Will test the mechanical action after work today. I'm guessing that the inoperative buttons on the door panel still point to the DDM. I think you should back up a little. Remove one at a time each splice and take a look at the connection. Nothing too hard at all. Solder if you feel the wires are no...

It's been a long time since I rummaged through a junkyard. Gonna need to find where they are these days. Anyone have a favorite in the Mpls-St.Paul area? I have tried many of the scrapyards around here & have come up with almost nothing for P2 stuff. That being said, there is a place in Glencoe...