Both my keys used to work fine. I had to replace the battery on one of them, and since I did this, it will no longer operate the remote locking. When the battery was brand new, the 1st couple of times I pressed the LOCK or UNLOCK button, the little red light lit and I think it locked/unlocked the doors. However, it then stopped working. No little red light. Almost as if the battery was dead again It will still start the car and drive it ok AS LONG as it hasn't been locked with the 'good' key previously. So if the working key locks it, and I open the door with the now 'bad' key, the car starts but the alarm goes off. Does it need reprogrammed? Is it hammered? Do I need a new one?