Just wanted to report that this all turned out OK. I went ahead and pulled the starter, took it to the bench and put the solenoid back on and reinstalled. The top bolt was somewhat difficult, but not too bad. Put her back together and.....CLICK.
Charged the batteries very slowly for 4 days, and......CLICK. Replaced the batteries and.....CLICK.
Pulled the starter AGAIN and bench tested it with some jumper cables.... CLICK.
Took the solenoid back off and put it back together, this time very carefully making sure the spring was seated properly. Bench tested - BINGO! Reinstalled on the truck and it started fine.....
I was then able to fix the original problem, which was that the something was draining the batteries. Disconnected both grounds and put a test light between one ground wire and the negative post on a battery. Sure enough it lit up. Pulled the red wire off the alternator...no change. Pull the positve cable off the starter relay - light goes out.
I went to the parts store and picked up a new starter relay for $10 and replaced it. Light still burns! Duh, there are 3 more wires connected to it, so could have something to do with those. Sure enough one of them, when disconnected made the light go off. This one disappears into a huge wiring harness.
Started pulling fuses one at at time. Pull all of them, then realize the driver's door is open (and so is the dome light, drawing current). Close the door and pull them all again, but the light stays on. Hmm.....
Then I remember the old CD changer a previous owner had mounted to the back of the cab, never has worked. Took some brackets off to remove the changer and found the cable where it plugged in, pulled it lose.....LIGHT OUT!
Can't believe is has been that blamed CD changer all this time! That thing is in the garbage, unfortunately the control head was epoxied to the dash and I can't get it off. But it is no longer sucking current and the batteries should hopefully now be fine.
