A couple weeks ago my central locking began working oddly. The central locking feature worked when pushing down on the driver's door lock knob or when locking or unlocking with the key; however, pulling up on the door lock knob would not unlock the other doors. Next to go was the unlock feature using the key - Now there was no central Unlocking at all, central Locking still worked. Its present state, which began a few days ago, has no central locking or unlocking with the key or with the knob.

I don't suspect the individual lock motors, as all doors are affected. Perhaps the driver's door lock switch? How would you test this switch? Is there another relay, switch, or anything else that would cause this problem?

Thanks a lot guys.

Trey