While your Jeep might not require the key in the ignition, it DOES require a charge cable to the battery!
The auxiliary braking system has an onboard compressor that cycles every time the brakes need to be applied on the TOAD. That will drain your battery on a single trip. I learned this first hand, which is why I added the charge wire to mine.
Sounds like you found the issue. I would definitely trace that wire back to the battery, and add a 15A fuse close to the battery. This will prevent any meltdown due to a shorted wire.
