Nissan Repair: BATTERY DRAINS, rear quarter panel, nissan maxima

Question
I HAVE A 1998 NISSAN MAXIMA WITH 120,000 MILES ON IT THAT DRIVES VERY WELL. THE ONLY PROBLEM I HAVE IS THAT IF I DON'T DRIVE THE CAR EVERY DAY THEN THE BATTERY GOES DEAD.  MY MECHANIC CHECKED IT OUT AND SAID THERE IS SOMETHING IN THE INTERIOR MODULE THAT IS EITHER STAYING ON OR DRAINING THE BATTERY BUT SINCE THERE ARE SO MANY THINGS IT CAN BE HE WASN'T ABLE TO ISOLATE THE PROBLEM. HOW WOULD I GO ABOUT FINDING WHAT IS CAUSING THE BATTERY TO GO DEAD AFTER 2 DAYS?    THIS PROBLEM STARTED AFTER THE CAR WAS IN AN ACCIDENT. THE PASSENGER SIDE REAR QUARTER PANEL HAD TO BE REPLACED. I'M NOT SURE IF THIS HAD ANYTHING TO DO WITH MY PROBLEM.

Answer
Jeff,

There should be nothing back there that would stay on unless your antenna is back there.  If the ground was not connected to the relay/motor that could cause it.  If not, what you end up doing is removing a fuse at a time and let the car sit and find out if pulling that circuit, like the radio first and if the car does not die you found the problem.  You repeat this process until you find the iffending circuit.  Otherwise, a mechanic is going to get an inductive volt-ohm meter and spend a day or two tracking the problem down.