Malibu 2006 - Remote Control - Unlock
 

The unlock door of my remote control is not working at all - however, the other ones are working fine (start - horn - trunk - lock).
I noticed when I opened the remote control that the tiny rubber part (dark black) on the "unlock" side is worn out when you compare it with the other ones and I am assuming that's the reason that the remote does not unlock the car.

What is that tiny black (dark) spot on the rubber is made of? How can this be fixed?

Any help would help!

Thanks Alain