DIESEL HARD START/GLOW PLUG FAILURE-BAD G/P CONTROLLER

VEHICLES AFFECTED: C, K, G, P - 1, 2, 3 With 6.2L Diesel Engine (1982-84)

The glow plug controller has three (3) internal circuits: a pre-glow timer, an after-glow timer, and a circuit breaker. A failure of the pre-glow timer will cause the circuit breaker to operate. The fact that the circuit breaker is controlling the glow plugs can be determined on a cold start by observing the glow plug light on the instrument panel. If the pre-glow time IS working, the glow plug light will continue to cycle on and off with the ignition key on and the engine off. If the pre-glow timer IS NOT working, the glow plug light will only cycle once with the ignition key on and the engine off.

If it is found that the circuit breaker is controlling the glow plugs, the glow plug controller should be replaced. Extended operation of the glow plugs with the circuit breaker can cause premature failure of the glow plugs.

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.