just boughtmy first merc and am presently having trouble with the keyless entry. I think it is an after market set up as it has no mercedes emblem.....all it has is atv 1.....fcc id;l2m443.....have searched the net for some clues , but all have come back blank....For some reason it will sometimes lock the car and sometimes it will unlock the car....but not all the time.....i dont know if it just needs reprogramming or if it has gone bad....ive changed the battery and that hasnt changed anything....hope someone out there has the answer....apart from that the car is fantastic....dave

 

what model?what year?polish the front of the red emitter gently with some light rubbing compound,wipe it off.Aim at the door handle that is where the reciever is located.Since it is infrared it is only good for about 6-10 feet so always make sure you are in range.
ohlord

 

His profile says a 1993 300E

 

sorry guys.....it is a 1993 300e....ive just checked the key fob and it doesnt have a red area at the front to clean....any more ideas????

 

I should have looked at the profile.Yours is just rf so you need to aim it at the rf receiver.
members at mbworld.org w124 section may have more ideas.