THe car is old enough that dealers are done with them - remember, you are driving a Mercedes SLK320 with a different body and altered electronics.
Chrysler dealers dont' want anything to do with your car, and the guys in the service department hate the car 'cause it makes them look stupid when they are not stupid.

Ok, if the lights flash, the FOB is fine. This is a pump issue - the locks are pneumatic, that is, a pump in the trunk operates them.
If your car is a Coupe, lift up the mat in the trunk and find the pump (it has a bunch of yellow hoses going to it). Did it, somehow, get wet?
Because wet pumps are a major cause for this kind of complaint. YOu can also start checking fuses in the big box under the hood on the driver's side, but I'd look at the condition of the pump first.


NOW, to PROVE what I've said, get in the car and start it. Use the button on the dash to lock and unlock the doors - if it doesn't work, look at the pump and fuses.
If it DOES work and your FOB doesn't - Im lost. That would make little sense, since the controller is flashing the lights THINKING the doors are being locked and unlocked.