K 3500 Truck 4WD V8-6.5L DSL Turbo VIN S (1999)
Fuel Heater: Description and Operation
The fuel heater operates when the temperature of fuel at the inlet of the filter housing is cold enough to possibly cause waxing that could restrict flow to
the injection pump. A control circuit inside the fuel heater completes the circuit for the heater element when it senses a temperature below 8°C (46°F).