Truck won’t start

does it start when you are putting a screwdriver thru the solenoid.

 

I am not sure about your truck, but on my Volvo starter overheat protection was messing up. I cut off the wire that goes to relay and grounded it to the cab.

 

need to check the mag switch, you should have power on one of the big posts and the other should go to the starter, one of the small post should have ground and power should come from ign switch in the dash. need to check what you have missing when someone is trying to crank the truck, most likely overcrank protection is possible, also bad wire between ign switch to mag switch possible.

 

In your other thread you talk about black in the coolant and pressure blowing coolant out of the reservoir. I wonder if you are getting coolant on toop of one of the cylinders and it is hydro locking on you?