95 7.3 no crank

Starts fine with bypassing solenoid but small wire is not engaging solenoid and no power on small wire that engages solenoid. Clutch switch replaced first and new batteries and new alternator - reason for that is - well here is the whole story. My son is 17 - good son but knows enough to really screw up while I’m at work. This is his truck so here goes. He tries to jump tractor off and hooks up wrong big arc hence new alternator and new batteries then when replacing batteries he hooks up batteries wrong then new alternator. Now it won’t start without bypassing solenoid. Solenoid probably good just not getting juice from switch. I’ve looked at fuses and link fuses and all seem to be fine. I’m looking for the reason solenoid not clicking when key moved to start positi9n. Is there a relay or fuse I’m missing ? Because I’m thinking that’s the problem just can’t find it in either fuse box. Batteries that were in it were fairly new but he got them to replace for free so he’s only spent 150. For alternator but he only got paid 200 for the job he was on when screwing all this up. He didn’t tell me about any of this until truck wouldn’t start late that evening. So this is where we are at now. Any help appreciated