TEMPERATURE CONTROL NOT ACCURATE - C/K TRUCKS. GMC Truck GMC K Pickup

VEHICLES AFFECTED: 1988 C/K MODELS WITHOUT AIR CONDITIONING

Some 1988 C/K models without air conditioning may have temperature control cables that will not adjust properly:. This condition is due to the cable adjustment ratchet having insufficient tension. Vehicles with this condition will experience either of the following symptoms:

a) Cool air from the heater or defroster vents when the temperature lever is in the full warm position.

b) Warm air from the heater or defroster vents when the temperature lever is in the full cool position.

To repair this condition, new temperature control cables have been released. P/N 15606998 - Base Heater P/N 15606999 - Heavy Duty Heater (RPO C42)

Cable Adjustment Procedure

- Initall new cable to heater control assembly and heater case.

- To adjust the cable, move the temperature lever to the full warm position.

Notice: Some resistance and a ratcheting noise will be noticed toward the end of lever travel. This resistance and noise will be experienced during the first adjustment only. Once the lever is moved to the full warm position, correct adjustment has been achieved.

Effective with the following VIN breakpoints, new cables have been installed in production.

Oshawa Chevrolet J1132635 GMC J1511630

Pontiac East Chevrolet JE117213 GMC JE505233

Fort Wayne Chevrolet JZ116479 GMC JZ504882

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.