Hello!

I own 2002 volvo s60. Car is in good condition (we recently went through diagnostics) but we have one problem - rear(back) doors won't unlock or lock when using central key. Basically I have to stick my hand behind my chair and open doors with handle that is inside. And when I want to lock the car, I need to open door and push in lock manually. It is kinda annoying and I'm afraid that once I will forget to lock doors.

 

Rear door locks get their signals from the REM, Front locks from DDM/PDM (rear electronic module, drivers/passenger door module)

On the diagram 3/76 and 3/77 are the rear door lock motors/assemblies. Maybe relay 2/115 in the REM is not supplying power to the violet wire when it's supposed to. Most of those relays are the same - so an easy test would be to swap one into position RMI 3. Note the relays are not drawn in the order they are arranged on the REM, and your car will not have all of those listed. So be careful when moving things around - it's easy to get confused and put a relay where it does not belong because you forgot where it came from.