Infrared key sensor on door handle inop after body shop, 97 C230
 

This problem has been going on a while, since coming out for a door replacement in May. The sensor body got crushed in a side-swipe, so it was replaced at the body shop with a new unit. It will not light up (red/green) and it will not lock or unlock the car. Body shop did a disconnect/reconnect, same issue. I guess the sensor could be DOA, but I find that unlikely. Another possibly-related symptom is that built-in foglights work intermittently since it came out of the body shop. I'm thinking the connection point may be related, or there is a single point of failure. Any ideas?

Have you tried the re-syncro process?

What's that? :)

If the key locks/unlocks thru the mirror receiver & the trunk, the problem has to be in that door.

The key is synchronized to the whole system not just 1 receiver.