VOLVO 850 - Rear door interminitently locking

reptar · Post by **reptar** » 23 Jan 2025, 04:20

Hi, I have a 1996 Volvo 850 Sedan, and I'm having issues with the driver's side rear door. When I unlock the car from the outside, the rear driver's side door sometimes stays locked and won’t open from the outside. This happens intermittently. However, opening the rear driver's door from the inside works fine every time. Any ideas what the fix is for this? Thank you.

Post by **scot850** » 23 Jan 2025, 16:13

The door actuators have a thermal overload resistor in them. This breaks down over the years to the point where the lock will either become intermittent or stop operating altogether.

Depending on your skill level, they can be repaired or replaced with a used one. There are threads on both on MVS.

Some replace the thermal resistor with a piece of copper wire. I do not agree with this as it removes the wiring system protection. That is each owners choice. If you don't get cold/freezing weather then it is less of an issue.

Buying a used actuator has it's issues in that it may well be as old as what you have and may not last a long time. A new one is expensive as I am not sure there is anything other than OE Volvo available. The RHR was NLA, but I think it has now become available again.

Neil.

Post by **abscate** » 24 Jan 2025, 02:35

I thought central locking involves sending lock commands to the 2/76 and then dispersing to the doors, which would preclude a solenoid or motor issue. I’ll look at the diagram tomorrow when I’m plane bound.

reptar · Post by **reptar** » 29 Jan 2025, 01:06

Hi Neil, is this the actuator part I require for a right hand side rear door?

https://www.ebay.com/itm/235615658438

Post by **scot850** » 29 Jan 2025, 14:15

I would suggest it is likely the part. However, in North America (I can't recall on 850's) cars often came with 2 stage un-locking, Never understood why this affected the door actuator as it is a 2nd press of the fob shortly after the first to get the doors to all un-lock. So basically if you press the fob once to unlock, just the driver's door unlocks. I you press it a second time all the doors unlock.

I'd confirm with a dealer with your Vin# which variation of locking system you have in your car so the part number can be verified as correct.

Neil.