Link btw driver & passenger lock actuator?
 

Slowly narrowing down and resolving problem with passenger door lock/window not dropping (fixed now), etc. only-by-one.

I'm now at the point where the passenger door locks and unlocks via the in-dash button and the passenger door unlocks when I unlock the driver door with the physical key. Driver door works fine for all of the above.

Problem though is the passenger door won't lock when I lock the driver door with the key. I've opened up the passenger door lock, checked all the microswitches, tested for voltage. I assume the passenger door lock itself is fine because it's locking with the in-dash button (i.e. it's getting the proper "close" signal).

There must be a signal from the driver door to the passenger door that tells it to lock when the key is inserted... which isn't working. Any thoughts on this? Should I open up the driver side door and lock actuator and see if something isn't working? What should I be looking for... or just bite the bullet and get a replacement for the passenger lock?

I have the Bentley manual and tried to follow the lock wiring diagrams, unfortunately not my forte.

Also as an FYI, key fob buttons don't do anything/alarm control light does not light up - next project to tackle.