the mosfet parts where u soldier is gound Not 12volts. the heater 12V is direct from the powers supply the mosfet control the ground.
back of board
pin 1 signal
pin2 direct to connector to heater
pin3 board direct ground
when signal is send to pin 1, pin2 and pin3 is connected
back of board
pin 1 signal
pin2 direct to connector to heater
pin3 board direct ground
when signal is send to pin 1, pin2 and pin3 is connected