CRUISE CONTROL RESPONSE MODULE MAY BE REPLACED

VEHICLES AFFECTED: 1988 G2 WITH 6.2L DIESEL (LH6) AND CRUISE (K34)

Some 1988 G Vans equipped with 6.2L light duty Diesel engines (LH6) and cruise control may exhibit a condition involving cruise control response. Accelerating and/or decelerating several mph more than anticipated may occur when the driver uses the Set, Resume, Tap-up, Tap-down, Coast, or Accelerate cruise modes. This may be caused by negative voltage transients during glow plug operation.

A cruise control module which is less susceptible to negative voltage transients may be installed.

Vehicles Involved

1988 GMC G2 vans equipped with 6.2L light duty Diesel engines (LH6) and cruise control (K34) built within the following VIN breakpoints:

From Through

GMC J4503836 J4509848 Chevrolet J4117090 J4130510

Parts

Part Part number Quantity ---- ----------- -------- Cruise control module 25074713 1

Service Procedure

Cruise control module replace. See Figure # 1

1. Disconnect cruise harness (121). 2. Disconnect module assembly (116) by prying back the retaining clip on the bracket and sliding the module out. 3. Install new module part #25074713. 4. Connect cruise harness.

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.