Key Will Not Remote Lock/Unlock Car

[jdonnee]

Hi all of a sudden in the past week my button on the key to unlock the car is not working. I have changed to two lithium batteries in the key and the car will still not open or lock. The red or green light in the rear mirror will not light up.

Is there a fuse or something I can check on the rear mirror?

Any other suggestion regarding possibly the key itself. The contact in the key is hitting the top of the battery.

[raymond~]

give car battery a look over. check voltage (under load), fluid level, specific
gravity.....to be sure power source is in good health. MB electronics require
good volts