Jeepngreg, You're problem has been gone long enough. Have you got the Jeep running yet? I have to admit I'm getting lost in the posts... so I propose you start over by doing a couple of things:
1. There's a differnece between the Jeep won't run, start, or the starter motor won't turn over:
a. Run: The Jeep engine will continue to run after it's started.
b. Start: The engine will crank, and fire up.
c. Turn Over: The starter motor appears to do nothing.
Using those terms I'm assuming the starter motor is not turning over and that you've tried varied wrining schemes to the starter solenoid and multiple starter solenoids as well. Is this true?
If so, then there a very basic problem you've dropped into... and you're lost as a kid in a corn maze. Here's how to get out:
1. Accuratley diagnois the symptosm.
2. Divide the problem in to what you know an what you don't know, what's good and what's not good.
3. Eliminate the good as the cause.
4. Concentrate on the bad as the cause.
So you know the engine does not turn over.
Have you tested these devices to insure they work INDEMPENDENTLY?:
2. Ignition Switch.
3. Starter Solenoid.
If these three devices work independently, they should work as a system and the problem is now down to a:
a. Wiring error.
b. Wiring harness break.
c. Termination error.
d. Wrong part for the application.
Grounds are important, and I'm sure you've checked them till you're blue in the face, but check 'em again with an OHM meter. You should have zero ohms when checking from the negative battery post to the:
2. Tub firewall.
3. Engine block.
4. Starter Motor Case.
If you measure the ohms between any of the above, as example Engine block to Starter Motor Case to the tub firewall it should be zero ohms.
If ANY reading does not comply, fix it.
Now, if you follow the above you know a few things:
1. The starter works and cranks fast and within it's amperage. How, because you took it off and tested it!.
2. You know the starter solenoid works. How, because you removed it and teste it with 12 volts and an Ohm meter. Let me know if you need help on this one...
3. The ignition switch works fine. How, well you removed/replaced it and before you reinstalled it you used an Ohm meter to confirm all the functionality of the switch.
So, if all the above is correct... then the problem HAS to lay somewhere else. Throwing parts at the problem will not help. So lets start to isolate the problem by removing the igniton switch.
Jumpering 12 volts to the right place will cause the starter relay to engage. Whe the starter relay engages 12 volts is sent to the starter motor and it engages.
Now ain't that easy? Yep, if you know how to jumper the starter solenoid. So now the question I've got to as is do you know how the solenoid is internally wired and how to jumper 12 volts to the solenoid to engage it? If not, stop right here and learn how.
Remember a starter relay is just that. It's a relay that opens and closes a set of contacts for the starter motor. When 12 volts is applied the relay closes and pulls closed the relay. When the 12 volts is removed, the voltage to the starter motor is removed. Simple as that.
The Starter Relay should easily sustain 150 amps current draw for a short time. There are differences between relays, some have two little contact terminals and some have three. Two of the three contacts are common, this one end of the solenoid pack coil. If you ground this point then you can apply 12 volts to the other free terminal and the relay should engage. You'll hear a click. Try it... it works...
Let me know what happens....