Non-Functioning IR Central Locking Feature

[MB-Dude]

The IR function for central locking in my ’96 SL600 has stopped working. My central locking feature works perfectly if the mechanical key is used in any of the locks. Thus, only the IR function is inoperable.

However, whenever I use the mechanical key to lock/unlock the car, the red/green lights on the rear view mirror are *not* blinking. I cannot remember if they blink whenever a mechanical key is used, or whether they are for IR operations only.

Question #1 – Can someone test with a similar vintage SL- or S-class, using a mechanical key, to see if the red/green indicators on the rear view mirror blink when using a mechanical key?

Question #2 – Assuming the non-blinking red/green lights (when using a mechanical key) imply the IR function is not working, what components make up the circuit? (Circuit board within the mirror is one, but what does it feed, etc.?)

Any and all input is welcomed! Thanks in advance.

Cheers,
Jeff