I don't know what 37Y/38BKO is.
Here is the way I would approach it...
***It starts when jumpered to the max fuse.
What is between the max fuse and the battery?
I think he said the alternator is 'between them'.
Show me the path. I need to see everything that is between the battery and that max fuse. In such a way that I can visually trace the path.
***If the alternator is the only thing between the fuse and the battery...
First of all, the alternator is charging up the battery. I don't think I'd mess with that setup, myself.
I would check the line that goes between the alternator and the max fuse. Better yet, I'd just replace it with a good 6ga or larger cable.
But... Next, why is there not a permanent connection, (jumper) between the battery and the max fuse?
I have 6ga lines going between the battery and the alternator.
Between the alternator and the point I think his max fuse is.
AND between the battery positive and where his max fuse is.
So there is a kind of triangle of 6ga wire there.
There is NO problem with that setup.
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Once you have that settled, and the truck starts and runs correctly, THEN you can start looking at the headlights and dome light.
Again, the headlights and dome lights should have absolutely no effect on whether the truck starts and runs or not.