thanks to an electrical schematic from rrgone, i was able to check all my inputs to the 4wd control module. i have switched and unswitched power, my grounds are good as is the signal from the neutral and brake pedal switch. i have ordered a new 4wd module, when i get the part installed i will update this thread. as far as the GEM module, it controls the wipers,power windows,rear window defrost,door alarms, etc.