Turn key, nothing happens. Need some help.

[Dizzle]

I searched for hours and looked through all the wiring diagrams, still no dice.

So here's what happened. Took about a 400 mile trip in my M1009, everything worked great. Next morning went to start it, everything lit up like it should, glow plugs went on, waited for the light, cranked it, starter turned about half a turn and things went dark. Figured it was a loose terminal or bad ground, checked them all, turned the key, and this time all the lights went on, but super dim and volt meter was way in the red. After couple more attempts, things went dark again for good. Now I get nothing, lights clicking, buzzing, nothing...

What i do know, both batteries have 12.7 Volts. The 24V bus has 26V and the 12V block by the GP relay has 12.7V . All the Fuses ans fusible links are good. None burned up. Hot lead on the stater was loose and looked like it was arching before, it might have shorted on the grounded starter body when everything went south. The starter is currently out to replace the damaged brass jumper from solenoid to the brushes, and both wires to the starter are isolated.

The strange things. I still have 26V in the 24V fuse on the fuse box with service lights off, when i flip on the service light switch, voltage in the fuse drops to 12.5V.
With the key on, most of the fuses in the panel test about 0.5 Volts. The lead to the GP solenoid has 26V in it with key off....the wire goes right through the resistor bank on the firewall, shouldn't it be 12???

Please throw any thoughts my way, even if it's just a wild guess. The truck is my daily driver and I'm out of ideas.

 

[Warthog]

First thing I would do is have the batteries checked with a load tester. Any of the parts stores should do it for you.

It sounds like a dead cell in the front battery by your description. I have a 6TL that does the same thing. Takes a charge, shows 12.5v, but as soon as you hit it with a load tester, it drops to zero.

In a stock system, the GP resistor pack and GP relay will have 24v with the relay off. As soon as the relay energizes and the glowplugs start heating up, the voltage will (should) drop to ~12v. When one gp fails , this voltage will increase from ~12v in incremental steps. As more plugs fail, the voltage keeps increasing until the last plug is getting the full 24v. It dies a very painfull death.

 

[Dizzle]

Thanks,
Can't have it tested today, but I can try tomorrow. I swapped batteries, front to back. In theory even if the back had dead cell or low volts, it should have lit up the 12V dash with good front batt. I had nothing still. I'm 90% positive that the starter lead grounded and caused an open somewhere, or something just failed from the short. Just don't know what. If there is a short, the batteries keep their charge, it might be only shorting when I turn the "service lights" switch, but thats only guesses.

PS
All the glow plugs are few month old no swells.

 

[dependable]

There is a heat shield above the starter that can fray the starter lead .

 

[topgun217]

Might want to check your grounds, after a 400 mile trip something may have gotten loose. My m1009 did the same thing a few times. I sanded all the grounds and replaced all of the batt. cables and waalaa ! Not a problem since then.