The remote key for my 2003 E500 has become intermittent. After the car sits for a while or overnight the key won't work. The dealer has replaced both batteries in the car as well as in the remote, I also have another remote key that does the same thing, so I'm pretty sure it's not the key. What could be causing this?

 

remove the batteries and then pushdown or bend down the contacts to better contact the batteries. this usually works and is 90% the problem.

 

Thanks for the advice, I will try this, but my old key won't open the car either, so I don't think its the key. any other possibilities?

 

I did try playing around with the contacts in the key, and put new batteries in, I also have another remote key and it doesn't work either. Still not working, it must be something to do with the receiver/antenna?

 

Have you tinted the windows?
Window tint can interfere with the remote signals.
Just a thought.