REVISED DIESEL GLOW PLUG SYSTEM DIAGNOSIS

VEHICLES AFFECTED: 1982-1984 C/K/P/G Trucks With 6.2L Diesel engines

The following is an update of the 6.2L diesel engine glow plug electrical system diagnosis. This should be used when diagnosing the glow plug system on all 1982-1984 model trucks with the 6.2L diesel engine, excluding the military (CUCV) vehicles.

With the connector removed from the glow plug controller, the controller bimetal heaters may be tested using a high impedance digital ohmmeter on the 200 Ohm scale.

CHECK READING

PINS 2 TO 3 0.40 TO 0.75 OHMS

PINS 4 TO 5 24 TO 30 OHMS

PINS 1 TO 5 117 TO 143 OHMS

PINS 2 TO 6 CONTINUITY ('0' OHMS)

If the controller does not measure within all of the above values, the controller should be replaced.

If the controller checks good to the above measurements, the harness connector should be put back on and ensure that the controller cycles on and off more than once with the ignition key on (engine not running). If the controller cycles more than once and the measurements are correct, the controller is good. If the controller cycles only once, the controller is bad or a harness problem exists. Refer to the Glow Plug Electrical System Diagnosis Chart for testing for a harness problem.

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.