yes, if by acc you mean the accessory fuse block or ACC on the ignition switch, the alternator/battery/ACC circuit is being completed, apparently via the heater unit and possibly depending on where alternator rotation stopped - shouldn't that 'factory plug' [DA plug?] have 2 wires? one that connects to a battery source to sense batt volts [usually back to the red wire on the big lug] the other to a dash light and/or the ignition sw via a diode, see here

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics