The other day, my electronic key died on me, so I tried using actual metal key to open the door. Unfortunately it would not work. I eneded up having to get a ride home to get my spare. My question is one, is this normal for the electronic key to die?...i thought it had a built in battery that charged while it was in ingition....if thats completely incorrect, how do i acces the battery(it was obvious to me)......two, on both my keys, the actual metal key does not open the door, but does lock the glove box. Is there some setting that has disabled my door from being opened manually?

I got the car used and dont have the manual, so i appreciate any insight.

mickey

The metal key should open the door - not sure why yours didn't. There are two batteries in each key and they do not charge from the ignition. It's an easy replacement. You can download a PDF manual from MBUSA.com

there is a trick to open with metal key. i learned when my battery dried and used mb help on phone to unlock my car.

step 1 : insert the metal key and turn it.
step 2 : pull the door handle to unlock the door.

Mercedes has made a change on some models--

The key for the new E550 coupe has only one battery--I was replacing them on 1 fob every month till we determined it was a faulty key--

The single is not expected to last as long as the pair so maybe they should be switched when the smoke detector batteries get changed.

Battery in key DOES NOT recharge while in the ignition switch.

I went to the MBUSA website and I can't find anything that shows me how to replace the batteries in the key... Can anyone either describe it or post a link? THANKS!!!

Here it is :

http://www.youtube.com/watch?v=yMSK3r_2cSE

Search youtube - you will find a lot of videos how to do it.

My 2010 E550 Coupe just had the "replace battery" warning come on in the dash. The car will be 1 year old March 27 this year, my local MBZ dealer gave me the replacement battery. I looked in the owners manuel and the battery was very easy to replace. It works and the "battery" warning went out.

Thanks! I found another video online a few minutes after I posted this. However, do I have to go to the MB dealer to get the batteries or does Walmart or some other retailer sell the same ones?

I actually went to my dealer - bought the batteries from them and the guy changed it for free. I paid about $15 for that. These are the regular batteries, that you can buy in any store, so I assume you Wall MArt sell it as well for much cheaper than $15. I'm just too lazy and not very handy to change it myself.

My wife's key is working only part time to open the doors. Found this helpful in our manual downloaded from the internet. Thought it might be helpful as the youtube vid is dead. I intend to replace with Walgreens batts and hope to not to have it synched with car.