Diagnostic System Check - Fuel Fired Heater. Chevrolet LUVW 2003

For 1990-2009 cars

Troubleshooting is normally limited to the isolation of defective components and provides information on defective wiring and connections.

The following possible causes for trouble have not been taken into consideration and must always be excluded as a possible cause for malfunctions:

• | Power supply to heater is less than 22 volts at main power connections (charge batteries and perform load test).

• | Blown fuses.

• | Corrosion on battery terminals for heater, electrical wiring, connections and fuses.

• | Loose contacts or connectors, wrong crimping on connectors.

• | Ensure heater and components have been correctly installed following all pertaining installation instructions.

### Troubleshooting Steps

After 3 consecutive unsuccessful startup attempts, the heater will lock itself out from any further start attempts.

The heater may also enter the lockout mode after experiencing an overheat condition. Before troubleshooting the heater, ensure heater is not in the "Lockout" mode by performing the following reset procedure:

• | Ensure switch is in the OFF position. Turn switch to the ON position. Remove fuse F1 (15 Amp). Refer to wiring diagram. Reinsert after 5 seconds.

• | Cycle switch OFF and then back ON once more. Remove fuse F1 once again and reinsert after 5 seconds. Heater should attempt to start in 10 seconds after inserting fuse. Coolant must be below the lower threshold before heater will attempt to start.