87 volvo 740 central door lock problem

SOURCE: REAR DOOR LOCK

you either have a faulty central locking motor or the wiring harness may be damaged.
Remove the door panel and check if you have a live feed to the central locking motor when you use the fob to lock or unlock. If you have power, then it will most likely be the motor that is at fault.

SOURCE: Volvo S60 - Problem with central Locking

You will need to replace the drivers door lock assembly, this is quite a common problem on this vehicle!

SOURCE: Volvo V70 Driver Door switches do not work

the main ground for the switch assembly is open somewhere.

SOURCE: volvo door locked but open so wont shut

ok ,try this,first unlock the door with the poweer locks then get a screw driver,what u do is where the pin in the door jamb would hit the door latch on the door put the screw driver between the two claw like parts that move inward on the latch and pull the door handle like you normally would and then pull the screwdriver towards the car at the same time,the two claw like pieces should rotate away from eachother and the door should close now,hope this helps

SOURCE: Hi 1995 Volvo 850 tailgate

it sounds as if you need to replace the lock assembly inside the door give these websites a try www.alldatadiy.com and www.autozone.com if all fails stop by your local Volvo dealership in the parts department and they be able to print you off the pictures and diagrams you will need wish you the best of luck Michigan Man.