Yesterday my driver's door handle keyless go buttons failed to work. No message displayed on the cluster. Passenger handle works fine and the car starts fine. Conventional wisdom seems to be that a new door handle is needed, but most of that wisdom is several years old so I thought I'd ask if there is another possible cause. The reason I ask is because there are two micro switches in the handle - one to lock and one to unlock - and it seems unlikely they would fail simultaneously. Is there some common component to those two switches that could be the cause?

 

Yes! water! I read somewhere on this forum once about a guy who took apart the handle (not necessarily w209, but the same system as our car door handle) and found that water had destroyed some contacts, he re-soldered and it worked.

 

FOUND IT! Second page a guy posted a picture of his handle torn apart, on the last page are 2 pdf files about repairing the handle itself.

https://mbworld.org/forums/w211-amg/...ement-diy.html

 

also since both microswitches failed together, id switch handles from left to right (just plug them in, they wont fit on the car) and test before taking apart the driver's handle.

 

Interesting thread. Good idea about swapping the passenger side first to see if that is the problem. Today it worked to unlock the door a couple times when I grabbed the handle because I forgot it was broken.