2008 startrans Ford E450 shuttle bus electrical issues

[VausHaus]

Hello everyone! I have a 2008 star trans e450 shuttle bus and all was great...

I bought this bus from an auction and it had no issues other than the wheel chair lift being removed and secondary batteries removed. One thing though, the positive battery cable running to the secondary batteries was wrapped with a t shirt and was hot. I moved it out of the way and TONs of sparks occurred. The radio, rear AC unit and entrance doors lost all power, but worked before... I used a voltmeter to see if they were getting power and nothing. I used a toner from the battery and got no signal to the fuse box for the millions of small electrical components secondary to the main electrical system. I then went to the fuse box and ran the toner in the other direction and it dead ends near the secondary battery box! They were getting power when the Tahiti was wrapped around the wire but after removing the wire I have no power. I'm thinking there might be an inline fuse, a relay or a switch blown somewhere but I don't want to guess. I ran a hot wire from an standalone auxiliary battery to the fuse box and vwalaa! Power. But what troubles me is that it used to be powered from the starter battery and I would like it to be so. Any help is greatly appreciated!

[sdwarf36]

It sounds like the lost things would all be for the 'bus" (as opposed to the 'Ford" section that rolled off the assembly line) On mine there is a 200 amp soleonoid that connects the 2 systems together when the key is turned. Do you hear any noise when you turn the key? Mine makes a big solid 'clunk' when the sol. get activated.
What battery are you missing-one of the two under the hood?

[VausHaus]

I figured it out. Just a loose connection at the battery terminal. I must have yanked on it when I removed the wire. Thanks for your help!