sorry, i didn't read through that well....

a solenoid is two separate components in one.....a magnetic coil and a switch. the magnetic coil makes/breaks the contacts on the switch....they do not have any physical connections what-so-ever. the only thing that can go wrong is the coil could short to ground, or the contacts on the high side could stick closed, or not make contact at all.

the easiest way to test a solenoid is to set a volt meter on ohms, touch it across the high side (batt/starter), then connect a 12 volt source to the low side (pos. & ground).....if your meter shows a Zero reading when the solenoid is energized, and infinity when when deenergized, it is good and your problem is elsewhere in the system.

I suppose there is a remote possibility of the contacts inside somehow grounding out, but it's pretty unlikely.

like red and magoo, i think your problem is with another component/wire.....