There is the big fat wire at the back, 12 volts all the time.
The 2 wire terminal has one 12 volt wire and the other is the light ciruit. When it is gounded internally the light goes on indicating no charge. When the circuit is open internally, the unit is charging and the light is out.
Make sure there is voltage to that wire key on engine off
Thursday, May 9th, 2013 AT 6:48 PM