Truck is a '96 F250 XL extended cab 4X4 manual trans.
It has had intermittent hard starting issues for a while that I have been putting off doing anything about.
Wednesday it started hard when I left for work and when I came home from work, and so required a lot of cranking. Work is only 5 miles away so the batteries probably didn't get recharged very well.
Wednesday night was pretty cold (high 20's) and I forgot to plug the heater in for the night. Next morning it wouldn't spin over at all. The batteries did not get drained as far as I can tell, all accessories work fine, glow plugs, ect., so I plugged it in for a few hours. Still wouldn't spin. Looking at the batteries I discovered the Ford dealer only replaced one of them the last time it was in the shop
(they did a bunch of other stuff I am not too happy about as well- another story).
I put a charger on it for a while. That only got me one revolution of the motor, so I went out and picked up a new battery. That didn't help at all. Took all three batteries in, and they all test good on Autozone's machine. There aren't any dead cells, according to my hydgrometer.
I tested the battery cables up to the starter and continuity is good. Grounds seem to be good as well. The truck is not dead (radio, lights, ect. work) but it just won't spin over.
Just want to know if I am overlooking something major here or if there's just some sort of short somewhere or if the starter is on it's way out or something. Any opinions are appreciated.