I've been having starting issues with my 2000 F150 with the 4.6L. After not getting the engine to turn over one day, I found that the wire lug on the positive lead (coming directly from the battery) had corroded and broke off. After getting a new lug crimped on and attached, I still was not getting the engine to turn over. I shorted the solenoid and was able to get the starter to turn, but the flywheel was not engaged.
I have been reading in places that the solenoid (on the starter, not the starter relay) also engages the gears within the starter to engage the flywheel. Is this likely the reason for my troubles, a broken starter solenoid? Or is there something else I should be looking at?
Of note, I voltage tested the trigger wire going to the solenoid from the starter relay and got ~10.5v. Also, while installing the new wire lug a friend said he was able to get the engine to turn over but I was not near the vehicle at the time.