2002 Saturn L300 climate controls shuts down

Both parts were used but known to be working. There was only one code in the system which was low efficiency on one bank but installed new cat and then cleared code with scanner. And has nothing to do with this problem. To program bcm there is a diy ritual with a timed key on ten mins three times and this is all sucessful as the car would not run without it. There is no programing for the controller. It works perfectly for an hour or so then screen goes blank as if lost power. Dome light does not come on during same time controller goes blank

I have no problem with fair donation if you come up with solution to problem

The programing is not the problem. The controller as I understand it is to upgrade or improve operation and does not address a complete blank screen
intemittent problem. The programing available for the body control module
is to address mileage and options but options are identical and again does not address the problem. LET ME EXPLAIN EXACTLY WHAT ITS DOING AGAIN. Sometimes it works sometimes it doesnt. Somtimes it will work for twenty minutes sometimes it will work an hour or two. And when it goes blank screen
all climate controls are inoperative. No ac no heater blank screen and no function at all. AND AT EXACTLY SAME TIME CLIMATE CONTROL DIES DOME LIGHT DOES NOT WORK. When climate control comes back to life then immediately begins working normally. This problem has been there since there since he got car recently. The problem was not affected a all by changing them. All parts have exact same symtom. There are no c
codes since clearing one unrelated code. Again power wire is hot when that powers screen is blank with power wire hot. This site is very hard to tyoe into the screen keeps moving and I cannot see what Im typing Im using android

I did consider checking dome light grounds. I did not check ground on controller yet either because I didnt have wiring schematic yet. I was hired by owner after he gave up on it to solve his problem. I did confirm his used parts work in other cars if the diy is applied correctly. When I was hired car would not run so I have been successful in a couple eliminating things and I agreed h Illr had a couple good guesses. I will let him know the things we need to check and get back tk you after I check them. Thanks Greg

Can you please tell me if this issue was resolved. I know this thread is a couple years old, but I am experienceing the exact same issue with the auto climate control in my 2003 Saturn LW300. Same issue - intermittent shut down of AC unit in conjunction with the dome light. Any onformation you can provide would be much appreciated. If checking grounds, where would I locate terminals.
Thanks,
Dave (not a mechanic)