Help with starting problem

[LrndTheHardWay]

So Ill try to keep this as short as possible. My daughter has an 04 Explorer with the 4.0, she went and bought a new car so the truck was parked near the beginning of winter, ran fine with no issues at that point. Her younger sister is getting her license so she decided shed give her younger sister the truck. Skip ahead to 2 weeks ago and I tried to start it, dead battery, charged it up and when I went to start it, the starter engaged, but there was a clunk, like the flywheel was frozen. After trying another 10 or so times, it finally turned it over and started it. Ran it for about 30 minutes at idle. Skip ahead to today and I went to start it, dead battery, completely dead, no lights etc, like it wasnt even there. No biggie, it was a cheap $50 walmart battery bought 2 years ago, so I bought a new battery, a good one this time, put it in, and it started to turn over, then quit, seemed like it froze again, now at this point I was having the new young owner turn it over (I actually had her put in the battery), so, I told her to try again, this time though, she held the key on way to long after it didnt turn over, but it did engage, same symptoms I had previously, thats when we smelled the burning wire smell. Was getting dark, and I was pissed, mainly because ALL of my cars have had issues lately and Im tired of working on them in the cold lol. So we called it a night and came inside. What Im really upset about tonight is we were supposed to swap out these rusty steel rims and bad set of tires, for an aluminum set with good tires from a guy whos parting his out. Postponed til tomorrow because of battery issue, but now Im not sure Ill even make it tomorrow after this flywheel/starter and wire problem.

My plan is to replace the wire and clean the connections because Im sure theres corrosion, but could that be my only problem? Would the corrosion cause it to not have enough oomph to turn the flywheel etc? Thanks for any help

 

[WaterBrat]

the starter initally pushes the small gear (I think it is called the bendix) into ther flywheel. Once it extends it triggers the circuit that spins the gear. If you mostly get clunking and no spinning it could be one of of things. either the starter motor or the solinoid. You can test by removing the starter and connecting it to the negative side of the battery with jumper cable, then you use the positive cable connected to battery to hit the connections to the starter. Know the starter on the ground will jump around so find a way to stabilize it. You have to jumper accross the solinoid terminals. I would reccomend this ONLY if you have thick leater gloves and a large screwdirver or pry bar with a heavy handle to jumper the terminals. You are looking for the bendix to extend and then spin. I had a bad solinoid on my V8 Ex that extended but did not spin and then pulled so much current as to cause melted insulation on the wires. Good luck and be careful.