Surfer69E500

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.

juanmor40

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.

KEY08

Yes, the fob will start the car with no battery if placed into the key slot.

cetialpha5

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.

Surfer69E500

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.

KEY08

Glad you got it going again. perhaps the led diode came unattached. I wouldn't worry about that. I might look at that light only once a year myself.