No LED light on Key Fob after new bat
Thread Starter
Junior Member
Joined: Jan 2015
Posts: 45
Likes: 9
From: Los Angeles
2004 E500
No LED light on Key Fob after new bat
2011 E350
Last couple of days regular key Fob stopped working but car still starts when in the ignition. (not keyless go). Replaced battery but LED doesn't light when pushing buttons.
Just want to confirm Key Fob is no good? Might try purchasing another battery just in case of dud. I did read all the post history.
Last couple of days regular key Fob stopped working but car still starts when in the ignition. (not keyless go). Replaced battery but LED doesn't light when pushing buttons.
Just want to confirm Key Fob is no good? Might try purchasing another battery just in case of dud. I did read all the post history.
MBWorld Fanatic!
Joined: May 2021
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From: US
2008 E350, 2012 ML350, 2014 E350, 2015 ML350
2011 E350
Last couple of days regular key Fob stopped working but car still starts when in the ignition. (not keyless go). Replaced battery but LED doesn't light when pushing buttons.
Just want to confirm Key Fob is no good? Might try purchasing another battery just in case of dud. I did read all the post history.
Last couple of days regular key Fob stopped working but car still starts when in the ignition. (not keyless go). Replaced battery but LED doesn't light when pushing buttons.
Just want to confirm Key Fob is no good? Might try purchasing another battery just in case of dud. I did read all the post history.
Either the battery drained (bad luck for a new battery), or it is not sitting properly within the fob.
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Joined: Oct 2005
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As far as I know the battery is not needed to start the car, or unlock the steering wheel. If the car is already unlocked you can verify removing the battery from the fob, and start the car.
Either the battery drained (bad luck for a new battery), or it is not sitting properly within the fob.
Either the battery drained (bad luck for a new battery), or it is not sitting properly within the fob.
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,190
Likes: 1,550
From: MA
2008 E350 4Matic, 2011 E350 4matic
Where did you get the battery? Multimeters really aren't that expensive and would be much cheaper to check the voltage of the battery instead of getting a new $300-$500+ key. Either the battery was a dud or it's in backwards. Check the voltage and report back. And even if there's nothing wrong with the battery, I'd try a can of electrical contact cleaner on the entire fob after having the battery out for a couple days before giving up on it.
Thread Starter
Junior Member
Joined: Jan 2015
Posts: 45
Likes: 9
From: Los Angeles
2004 E500
OK so all I did was pry the little tangs inside up a little bit and all of a sudden it is functioning again but still no LED light turns on the Key Fob? Dont actually remember seeing it work before now that I think of it.
Now thinking forget the LED light it could have had something to do with Aux Bat error message I am getting occasionally if it wasnt the FOB bat. TBC. Let's see if it lasts.
Now thinking forget the LED light it could have had something to do with Aux Bat error message I am getting occasionally if it wasnt the FOB bat. TBC. Let's see if it lasts.
