Volvo: Volvo 240 Central Locking problem, passenger doors, volvo 240

Question
I'll do that, no problem.  But, wouldn't the fact that the drivers door switch operates the trunk lock correctly mean that everything is ok there?
Thanks,
Don.

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The text above is a follow-up to ...

-----Question-----
I have a 91 240 Sedan with a central locking system problem.  The only lock that works is the trunk, which operates normally, lock/unlock, from either use of the drivers door key or push/pull knob.  The other 3 doors do not unlock or lock.  Since the trunk lock is working, I'm assuming that the relays are good. What wiring / connector is common to the 3 passenger doors that could cause this?
Thanks for your help!
Don.

-----Answer-----
Don,
I would pull the main switch and check the wires there. They are the ones that cause most problems. That is the switch in the left front door.

Answer
Don,
Well I see the logic behind your comment, so then take a rear door panel off and test the power to the lock motor. If there is no power trace it forward to the relays behind the center dash vents and then to the master switch in the left front door.