HEADLIGHT DIMMING AND ENGINE DRIVEABILITY COMPLAINT

MOMENTARY HEAD LIGHT DIMMING AND/OR ENGINE SURGE, HESITATION

VEHICLES AFFECTED: 1988 C/K WITH 100 AMP ALTERNATOR(K60) ----------------- 1988 C/K model trucks equipped with a 100 amp alternator, service P/N 10463045 (OE P/N 1105711), may experience a momentary alternator voltage drop. The voltage drop may occur at night on deceleration toward a stop and could be manifested by any or all of the following symptoms:

1. Momentary head light dim. 2. Momentary voltmeter needle fluctuation. 3. Momentary slowing of blower motor. 4. Momentary engine stumble, slight surge or hesitation.

The integral regulator in the alternator has been changed in current production to address this condition. There is no part number change. The new alternator can be identified by a date code 2018, or greater, stamped on the bottom boss below the part number (see Figure 1). The alternator is not serviceable and must be replaced as an assembly. Parts ordered will be the new ones discussed above.

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.