Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
If the remote locks stopped working with the key fob, it can only be 2 things. The first one is the key fob is not sending any radio signals to the locking computer. The second problem could be the antenna for the locking computer is faulty. Since the locking/unlocking works with the button inside, I doubt any thing is wrong with any of the locking computers. My advice would be to get the key checked at an auto parts store. I have seen some stores have a key tester that tests the key for a radio signal output. If there is no signal, then the key is faulty. If there is a signal, then chances are the antenna in the vehicle is faulty. I would call an auto parts store such as autozone first to see if they have this tool. If no one has it around you, then you can always go to a dealership to have the test done but you might have to pay. One last option would be to order a 2nd key, if you don't have one, and just try the key and even if the new one doesn't work, you will at least have a spare. Please let me know if you have any questions before you decide to rate me!