2008 gmc 3500hd intermittent electrical problem
July of 2018 my truck started resetting the clock ,the ac panel and at times barley starting. Stopped at a dealer in Kentucky the tech said starting and chargeing system was good but i had the wrong batteries in the truck they were the wrong size 730cca not 770cca both batteries were only four months old charged me 150.00 problem continued rest of summer. Got back to Arizona took it to a place that only does electrical work they had it for seven days and could not find the problem another 125.00 still have problem. I finally had enough i took it to my friends grage put it up on stands found all 10 grounds removed and cleaned them still had problem. Was leaning over passenger fender with battery removed noticed positive cable going to black box on fire wall removed the cover went to check connection found the cable from that battery going to the mega fuze block finger tight cleaned and tighten it its been a month and problem gone. Never give uup no matter what .
