Fuel Heater Inoperative: Description

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The fuel manager/filter assembly consists of the fuel heater, the water-in-fuel sensor, and a filter. The filter contains the coalescer, the device that combines small droplets of water into larger ones, and the filter/separator. As fuel enters filter, fuel passes through the fuel heater. The heater contains a thermostatic switch that opens or closes to turn the heater OFF or ON, depending on the temperature of the fuel.

The fuel then passes through the filter and water coalescer, where droplets of water in fuel combine into larger drops that fall into the water reservoir in the filter. When fuel flows from the fuel manager/filter assembly to the injection pump, the fuel is clean and free of water. The fuel heater is operated by a built-in thermostatic switch. The thermostatic switch completes the circuit for the fuel heater element when the thermostatic switch senses a temperature below 46°F (8°C).