I turned on the ignition key and jumpered from the positive battery terminal to the Engine Start wire on the side of the solenoid. I was able to get sparks but no other action...

 

Also note that while the in-dash voltmeter was indicating discharge, the cruise control continued to work normally, so the PCM seems to be functioning (at least partially).

 

FSS is on the front of your injection pump ( away from the gear side ) and is partially under the throttle bracket, here is a sort of picture of it, also a view of the starter and wires.



If you jumped to the small solenoid wire and nothing happened, then starter is toast, you can try smacking it a couple of times to see if it starts, but that is only a temporary fix.

 

Okay, thanks. It's certainly possible the starter died suddenly and has nothing to do with the charging issue I'm having.

I tried jumping to the small solenoid wire with a relatively small wire; I'll get a set of jumper cables and try jumping with those.

 

Ok, you can try, but it really doesn't take too much to bring the solenoid in, even an 18 gauge wire should suffice.

Try giving the starter body a few smacks while you are under there.

 

Thanks so much. Have now tried heavy duty jumper cables from positive battery terminal to small wire on solenoid, as well as three rounds of smacking the starter/solenoid with a small ball peen hammer. All to no avail .

So my starter died in the midst of my trying to figure out my charging problem. And of course the truck is outdoors in a steady rain. These First Gens look great but they do in fact have dependability issues.

Thanks for all the help; I will revert if/when I identify the charging gremlin.

 

They don't have dependability issues, any more than a "modern" truck. You've been seducing the canine on this charging issue for weeks.

It appears that your starter died. Starting with a low battery is very hard on starters, so no surprise.

If you get it running, and a test light or voltmeter in hand, call me and I'll walk you through charging diagnostics.

 

Okay, I'll concede I'm guilty on this point. But in my defense, it is tough to diagnose a problem that manifests itself for only two minutes at a time at 70mph.

Update:
I phoned the local AutoZone on Sunday night during the Super Bowl and they had me a starter (remanufactured in China) by 9am on Monday for about $100. After purchasing the new starter, on a whim, I turned the ignition key and the truck roared to life. (This was a Godsend -- it enabled me to get the truck into a carport out of the wind and onto dry concrete.) I replaced the starter but decided to keep my old starter (and forgo the $31 core rebate) because it is the OEM NipponDenso and I already have the "Larry B's" rebuild kit to put in it.

The reman. starter works fine and this morning I drove the 120 miles back home -- now the charging issues seem to have disappeared . Could my battery discharge problem have been something awry in the starter and/or solenoid? If so, when I open up the starter what do I look for to satisfy myself that my charging problem was not coming from elsewhere in the truck?

Thanks again to all to have chimed in; this forum is a lifesaver.

 

Not likely that the starter would do that at speed, at least without some smoke or gear grinding. I expect you to find that it's in relatively good shape except for brushes and solenoid.

You were messing with the wiring when the starter failed. You might have tugged on something that was intermittent. Chief suspect would be the heavy connector between the battery and the splice where the duck foot and the generator power cable come together.

Best bet, though, is don't just pull and tug on things if the bug comes back. We should set a trap to see if the alternator is fielding when it's failing, which would give us a definite route to follow to the problem.