'86 M923 New Owner- Electrical systems Troubleshooting

[Peacemaker39]

New to the Forum and new to Military trucks. Spent some time reading up on the site prior to purchasing...Looking for some guidance

Upon taking delivery I tested voltage on each of the 4 batteries. All four were junk. Carefully diagramed and photo'd the wiring scheme. Purchased 4 new batteries and it's gone down hill since..

I installed the new batteries carefully following diagram. I linked the batteries, then connected positive wire and saved the negative wire for last. (Typical for boats)... Upon touching the negative wire to the battery post non-typical sparking occurred. In addition the light(push button panel to the left of the wheel) switches began smoking. Called a buddy to double check the wiring and he confirmed that batteries should be installed correctly.

any thoughts?? Never seen anything quite like this

 

[Coffey1]

Don't know if it's your problem.
But there's been reports the positive cable gets the insulation rubbed off under cab and could be causing a short.

 

[Andyrv6av8r]

Post some pictures of your batteries and hookup. Did you follow the diagram under the seat bottom? In my cases of low voltage batteries, I've always been able to recover and reuse them with slow, low amp charging. Installing fresh batteries shouldn't fry anything if installed properly.

 

[98G]

That switch is suspect. The pushbutton switches are prone to fail spectacularly. Disconnect it and see what you've got.

Then replace it with a 3 lever switch.