Central Unlock Button Not Unlocking
 

I have an 89 C4. Recently, I've been noticing my car has an unlocking issue.

-Sometimes when I unlock the car with the key on the driver door, it won't unlock the passenger door.

-When I press the center "KEY" button inside the car, it locks the car, but does not unlock the car.

Has anyone had this issue or know of a part that may need replacement?

The control module is under the dash near the center tunnel, its a a little black box about the size of a pack of cigarettes, unplug it and open it, one of the pins has a connecting piece soldered to it and is known to come off..

Thank you. I will take a look at this and let you know what I find.