door lock issues 01 cherokee sport

I have a vehicle here that will occasionally not lock or unlock. When the situation shows up, it will not lock or unlock from either of the switches mounted to the door, or the aftermarket alarm remote. It will work fine for days on end, then it will not work for a day. Very random and you have no idea when they will or won't work. I have done some research and they say that there is a keyless module in the overhead console. My question is, has anybody seen the same problem, and what did it turn out to be?

Have you tried the obvious Craig, disconnect one of the battery terminals and touch them together? Failing that power supply and grounds, failing connections?