Prius 2007 shorted Circuit

Hi All,
My prius 2007 battery was dead this morning, the car could not start due to low battery level. I asked my neighbor to borrow his car for a jamp start, the car started normally. I drove to a national park near my city and I smelled burned wire and acid, I stopped the car and checked the auxiliary battery and it turned out to be very hot and the aux battery wiring to the front engine bay was very hot. I powered off the car and used my multimeter to measure the charging voltage(14.6 turned out to be normal) but when I measure the current it read 1.5A while the car powered off, no light on, everything turned off. I pulled out all relays in the engine bay and pull all the connection harness to both front seats, pulled out all wiring to steering wheel column, the current still steal read 1.5 to 1.6A. I think it was a short circuit, but I could not find the place where the short happened.

Please help me, any idea or input is very helpful and appreciated.