Question for the forum. I have a 1996 C280 Sport with the vacuu, operated locking system. Just recently as the weather got a little colder the rear passenger side door will not unlock when all of the other doors unlock and there is a whining sound for about 10 seconds. The lock moves up and down manually just fine and will lock when the other doors lock, just not unlock.

As it warmed up later in the day, the lock would lock and unlock witht the other doors. Any ideas on how to repair this issue?

Thanks!

 

Sounds like a seal is going bad but is not yet totally bad so when it is warm it is expanded enough to seal but when it gets cold it shrinks enough to not seal. It might be the actuator in the door or with the tubing.