Starter solenoid

[JohnEd]

Don't neglect that the original design worked when the bus was made.  And Lin's / Don's advice is oh so valid.

That glowing wire was not a fuseable link.  You are SOL.  Low voltage will destroy a starter and your story about the engine "just barely" turning over spelled the death hell of your starter.  As far as I am concerned.  Take your starter in for a full diag and bearing and brushes refresher.  Keep testing, but brace yourself for that.  You can do all that yourself but the undercutting of the armature takes a lathe and a shop should do that.  Low battery voltage will cause the starter to draw MORE current. 

Charge you bats.  Test them with a load tester.   Measure the voltage across the starter when you hit the start button.  Connect the volt meter across the + cabling from the bat all the way to the starter terminal and get a reading when the start button is pressed and this should not be greater than 10 or 15 percent of the bat voltage and can be gotten much lower with maticulas cleaning and tightening.  Measure the voltage from the starter frame to the neg terminal and hit the start.  note that that voltage can certainly be brought down to only a fraction of a volt.  If you starter windings are burned open then your solenoid should still click loudly.

I urge you to call a shop and get a reading on the validity of these tests and the info each will give you.

A pick-up bat and alt won't do much to start your engine.  They will certainly charge your bats however.  If you connect up to a dead bat and then try to start remember that your engine starter will only get what is left over from you truck trying to charge your bats.  Connect it up and wait 30 minutes at least before hitting the start.  And if only crawls stop and wait till the two can spin it proper.  Your starter is at risk.  Glowing red wires should be replaced with wires of a larger size with insulation on them.