remote keys suddenly only work part time!?

[pippy0]

Hi all got a '53 c180k sports coupe.
No problems with it whatsoever until today.. the central locking has worked from opposite ends of a carpark with no issues..
Today i go out and neither remote worked.. even if i held it right up to the handle. Changed the batteries in 1 key and it unlocked the car, but wont lock it again.. key 2 then worked for a while, unlocking and locking but only at very close range to the door.
I've recently replaced the headunit so all the centre dash has been out and also have had the windows tinted.. but cant see that being the issue as the locking worked all day yesterday..
Any Clues?

 

[pippy0]

checked all fuses etc... all fine, came back to the car an hour later and now the locking all works as it should! Confused.. yes... but still.. it works

 

[Diesel Benz]

The 203 sedan often has connectivity problems at the rear window area where the antenna amplifier connects to the antenna wiring at the rear window. I don't know if it is the same for the Sports Coupe. Here it my help if one pushes up the roof panel from the rear (just for testing,).

It should still work from the IR receiver, must be at the driver side door handle in this car. Did you point the IR receiver with your key?

Unlikely a key issue if both keys behave the same way (and key problems usually bother owners who have only one key ).