Searched the Tech Help, but couldn't find anything related.
Maybe someone has some suggestions for troubleshooting the following power lock and infrared remote problems which I'm experiencing with my 1990 300SL (R129):

- Driver and passenger side door locks cannot be operated with the key. The
key works fine with the trunk lock, though (locking/unlocking the whole car).

- Infrared remote works very unreliably (new batteries installed):
- remote does not work in the morning after car has been parked overnight
(driver, passenger door and trunk)
- after driving car for a while remote function typically comes back,
sometimes on driver side, sometimes on passenger side, sometimes on
both, but not on trunk. Remote function then works for a while (on doors), but will be
off again after car is parked and not used for a period of time.
- found out that remote function works reasonably fine when it's dark outside
- also found out that when remote does not work during the day it DOES work when
held directly to the infrared sensor in the door handle (only on driver side, though).

I don't know if the remote and key lock issues are related or have to be troubleshooted separately. Appears, that the issues with the remote have something to do with the IR sensitivity of the system ?

Any help highly appreciated.
Thx.