The ground is not at the battery. It is grounded at the same spot that the battery is grounded to. Same for power. Not directly at the amp, but at the bolt in the floor where the stock + wire goes to.

The lights on the Helix stay on when the Helix disconnects from the software. The Zapco (sub amp) green light goes out when it stops working.

I have not tried removing the Bluetooth HEC. But could that really be a problem if the sub amp is also experiencing a similiar issue (not staying on for more than 15 seconds)?

The Helix was purchased from a member here and is supposed to be new never used.