87 ford f-150 electrical woes

I found where somebody had tried to steal the battery out of my truck.I had started it previsoly about every week to move it to mow the yard . About a week ago I went to move it and the battery was dead and the light switch was pulled out to the parking light location.Tried to charge the battery and it's shot ,so I stuck another battery in it and the positive terminal gets hot and you can't even cross the cylinoid to try and start it there aint no juice getting any where. no horn no dash lights no nothing . I checked the wiriing from the terminals to the starter and to the cylinoid with no problems found.Please if there's anybody out there to give me an idea what to look for this is the place to find it . Thanks David

Are you sure they were not trying to steal the whole truck?

There are few wires or circuits in the truck that are not protected by fuses or a fuseable link.

The starter solinoid is one, as you pointed out. Another is the alternator, and another is the main power going into the steering column. Also, there should be a power wire going to the fuse box.

Look at all these wires for damage.
Look at the starter solenoid itself first. Possibly in an attempt to jump the solenoid they have damaged it and shorted it out. It takes a HUGE current draw to heat up a battery terminal and IMO a short in any other wire other than the solenoid would cause wire overheating/smoke/fire that would be obvious..

I suspect the column or under the dash is also a good place to look. Look for damage, cut wires etc from an attempt to steal the truck.

Also, a digital multimeter is handy. The ohm meter setting can help you look for shorted circuits, current flow etc.

Thanks for all the advice, I checked all the wireing under the dash under the hood found no problems with any of it . So figureing that all the power runs through the cylinoid it has to be shorted out, bought a new one stuck it in and bingo started and ran good like it had in the past . the only thing I can figure is whoever tried to steal the battery when they put it back in they put the terminals on wrong . At least the battery was'nt that good and it did'nt catch on fire.