97 peterbilt 379 3406e no start

Truck won’t start. It’s a 97 Pete with a 3406e. It started a couple months ago. The key gets power but when I pushed the button nothing happened. No clicking or anything. Just the solinoid engaging and then it would go dead like the batteries were drained, I found a hot to the touch ground wire and traced it. It went from the negative terminal on the first battery into the dash and was bolted to a piece of metal. I disconnected it and the truck started. Didn’t have any issues until 2 days ago when the starter would click but wouldn’t turn over. Banged on the starter and it fired up. Ran it all day and didn’t have any further problems. Yesterday i had the first issue and found a hot to the touch wire that went to my webasto engine heater. Disconnected power and ground to the heater and the truck fired right up and started with no issues the rest of the day. This morning I’m having the same problem. This time I can’t find any more wires that could be causing the problem and when I hit the push start it goes dead only it won’t recover this time by resetting the ignition.
Any suggestions?
Thanks, Kris.

 

Update*** the truck started after I disconnected the batteries and reconnect them after 30 seconds.
Which can only mean I was inavertadly doing this when I was disconnecting the random wire and the webasto heater.