Relays
All the relays are 12 Vdc relays. The relays on the microprocessor PC board are interchangeable. The relays mounted on the inside of the control box are interchangeable. The relays on the microprocessor PC board are not interchangeable with the relays mounted on the inside of the control box. Test a relay by interchanging it with a known good relay.
Ignition Relay
The Ignition relay (RL1) is located on the PC board. It supplies power to the ECU. The RL1 LED on the PC board will light up when the Ignition relay is energized.
Run Relay
The Run relay (RL2) is located on the PC board. It supplies power to the ECU. The RL2 LED on the PC board will light up when the Run relay is energized.
Fuel Pump Relay
The Fuel Pump relay (RL3) is located on the PC board. It supplies power to the fuel pump. The RL3 LED on the PC board will light up when the fuel pump relay is energized.
Start Relay
The start relay is mounted on the inside of the control box. It is energized by the controller after proper preheat time has occurred. When this relay energizes, the starter solenoid receives power and the engine cranks. If the start relay fails in the open position, the engine would not crank. If the relay failed in the closed position, the starter would continue to crank after the unit started.
Preheat Relay
The preheat relay is mounted on the inside of the engine compartment. It supplies power to the glow plugs. If the preheat relay fails a P code will be generated in the ECU and the controller will display a message.
PC Board Relays
| 1. | Spare Relay (If Installed) | 3. | Relay RL2 - Run Relay |
| 2. | Relay RL3 - Fuel Pump Relay | 4. | Relay RL1 - Ignition Relay |