For 1990-2009 cars

# DIESEL FUEL LINE HEATER NOW AVAILABLE

TO PREVENT FUEL SYSTEM "WAXING" IN COLD WEATHER A FUEL SYSTEM HEATER IS NOW AVAILABLE ON DIESEL ENGINE EQUIPPED MODELS. THIS OPTION, K07, IS ONLY AVAILABLE WITH THE ENGINE BLOCK HEATER. THE DIESEL FUEL HEATER IS A THERMOSTATICALLY CONTROLLED ELECTRICAL RESISTANCE TYPE HEATER DESIGNED TO HEAT THE FUEL BEFORE IT ENTERS THE ENGINE MOUNTED FUEL FILTER TO REDUCE THE POSSIBILITY OF WAX PLUGGING THE FILTER AT TEMPERATURES BELOW 20F. BATTERY VOLTAGE IS DIRECTED TO THE HEATER (FROM THE DIESEL PUMP FUEL SOLENOID TERMINAL) WHENEVER THE IGNITION SWITCH IS IN THE "RUN" POSITION. THE HEATER CONSISTS OF A THERMAL STRIP SPIRAL WOUND AROUND THE LIFT PUMP TO FILTER FUEL PIPE. A BI-METAL THERMAL SWITCH SENSES THE FUEL TEMPERATURE AND CLOSES THE ELECTRICAL CIRCUIT AT ABOUT 20F. THE CIRCUIT OPENS AT 50F. A THERMAL FUSE PROTECTS THE ELECTRICAL SYSTEM. SEE ILLUSTRATION. ** A BY-PASS VALVE IN THE FUEL TANK FILTER (SOCK) OPENS WHEN THE TANK FILTER IS COVERED BY WAX, ALLOWING FUEL TO FLOW TO THE HEATER.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.