1985 M-VAN, S/T TRUCK, AND CABALLERO
Some 1985 M-Vans, S/T Trucks and Caballeros may experience a no run or no start condition, and/or blown fuel pump fuse due to an inoperative in-tank electric fuel pump, which may be due to a short in the radio frequency interference (RFI) fliter. The RFI filter is located on the electrical input terminals of the in-tank electric fuel pump.
To check, disconnect the three wire connector at the fuel tank and measure the resistance between the two outside wires of the connector going to the tank (black and tan). A resistance measurement of 3 to 4 ohms indicates a good unit.
To check further, remove the tank unit assembly and measure the resistance of the RFI filter and pump assembly individually.
Resistance of good RFI filter - infinity (open circuit)
Resistance of good electric motor - 3 to 4 ohms
If the RFI filter is shorted, replace filter with kit P/N 6472779.
If electric motor is inoperative, replace pump with kit P/N 6472311.
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.