1999 Mercedes Benz ML430 my remote to lock and unlock

Electrical problem
1999 Mercedes Benz ML430 Four Wheel Drive Automatic

my friends battery died in her mercedes ml 430 and so we took it to Checker to get it charged and it wouldnt take a charge so she bought a new battery and I put it in and the remote doesnt seem to want to work, we bought new batteries for it and still nothing, is there a fuse somewhere in the fuse box that I cant seem to find that may have gone bad? Or could it be the AAM located under the fuse box that could be the problem, and if so how difficult would it be for me to fix by myself? Thank you Fred