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start the truck, and take off the neg cable off the battery. If the truck shuts off, It's the alt or the connection from the alt. That's where I would start.



Typically, not the best procedure. While nothing detrimental normally happens, all the conditions are right for electrical mishaps. Better to take it to a parts store (independent, preferrably) and have them test the entire system using a handheld like a Midtronics.

BTW, x2 on the alternator being the usual culprit.

Fasteddy's advice is occasionally sound...