2003 SL350 central locking problem

[Peter James]

The central locking will only work if the key is held very close (almost touching) the door handle. I have 2 keys and either one is the same. Key fob batteries are OK. The PSE unit works when the key fob is held close to the door handle therefore I guess the PSE unit is OK. Is the receiver for the key operation a separate unit or is it part of the PSE unit. If it is a separate unit where is it located?
Any help would be greatly appreciated

 

[Blobcat]

Hello and welcome

Keys work on IR and RF, sounds like your IR is working which is why it works so close to the car.
If the keys are dropped there is a coil inside them that comes loose and the RF side stops working.
However as both of your keys aren’t working then it could be the RF amplifier in the car that has failed.

 

[Peter James]

Hello and welcome

Keys work on IR and RF, sounds like your IR is working which is why it works so close to the car.
If the keys are dropped there is a coil inside them that comes loose and the RF side stops working.
However as both of your keys aren’t working then it could be the RF amplifier in the car that has failed.

 

[Peter James]

Thanks for that, that could explain the problem. Do you know where the RF amplifier is located?

 

[Blobcat]

Might be in the boot @LostKiwi will know the exact location

 

[LostKiwi]

Might be in the boot @LostKiwi will know the exact location

No idea... But I'll check my notes.

 

[LostKiwi]

Here's what I have.

The antennas are at the base of the windscreen (fine wires embedded in the screen).