Why Does My Mercedes Key Fob Battery Keep Dying. So I inserted the key fob in the Intelligent Key port. A different battery will have a different voltage and the system may not register properly even if the fob still works.
In case the metal was always in contact the red LED on the key FOB would have always been on which apparently was never the case. If the battery completely dies the fob chip will also lose power and become useless unless reprogrammed. I never had to go to the dealer and get raped.
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After replacing the battery in the key fob remote you will need to reprogram the remote to the vehicle. This is why nothing is working with the key fob. If your Mercedes key has lost its remote function such as unlocking doors or opening the trunk the keys own internal battery may be dead or dying. So I get the other key fob and it also suddenly needs a battery.
