Volvo: Central locking volvo 850 T5R Estate Auto 1995, volvo 850 t5r, volvo 850

Question
Both the tailgate and fuel flap solenoids work intermittently. Have taken petrol flap solenoid out and bench tested it and is functioning perfectly. Could it be a lack of power?

Answer
David,
I have not ever heard of some lock motors getting say 12 volts and others getting less. You can compare a working lock by measuring the voltage at the wires. I would say that the lock are getting weak. If you feel that the cause is not the motors, do your best in cleaning the locks of dust and dirt, make sure that the linkage rods are all in proper order and clean. Lub areas that can be lubed, but only where the lub will not collect dirt and dust.