Any help on this issue would be greatly appreciated! I think the truck is possessed!! Just kidding, well maybe not. Lots of trouble with the electrical system. Just changed sensor that shuts off truck when coolant low and fixed shorted wire. Now, after heading down the road thinking all is well, no power, blinking dash board lights and gages. At my wits end on this!! It is a gmc 4500 topkick 2007. Any ideas???
Start with cab and chassis grounds. Particularly the chassis to cab ground. Should be like a 10 ga black wire between the two. Make sure all are clean and tight. If memory serves, there should be an electrical distribution panel under hood. Top is covered nicely, bottom is left open to road spray. Check for corrosion. Lastly, up near cowl should be a load panel with larger 70 amp relays and heavy fuses. Check corrosion there as well.