Glow Plug Relays
Terminal No. 1 is an input for battery voltage on both relays. Terminal No. 2 is an output to the sensing resistor on relay No. 1, and an output to the dropping resistor on relay No. 2. Terminal No. 3 is an input from controller on relay No.1, and an input from the starter switch on relay No. 2. On both relays, terminal No. 4 is ground. See Fig 1 .