Three hours on a 'bad alternator' that was just a loose ground strap
Spent all Tuesday morning chasing a no-start on a 2012 F-150, swapped the alternator, tested everything, and it still wouldn't crank. Turns out the negative battery ground strap was barely touching the block, some corrosion and a 14mm socket fixed it in 5 minutes. Anyone else had a simple ground kill their whole diagnosis?
Been there with an old Chevy, swapped the whole starter and battery before finding the negative cable was cracked inside the insulation. Makes you want to slap yourself right in the face when the fix is just a wrench turn.