A/C & HEATER MODULE OPERATION AND DESIGN CHANGE. Buick Electra/Park Avenue 1987

For 1990-2009 cars

# A/C & HEATER MODULE OPERATION AND DESIGN CHANGE

HEATER MODULE AIR VALVE

#### VEHICLES AFFECTED: 1986 DELTA 88 WITH MANUAL A/C (60) -----------------

Beginning in 1986, a now A/C and heater module was used on the Delta 88 models with C60 (manuaI A/C), This new design is on the 1987 Delta 88 and Ninety-Eight models with C60 (manual A/C).

This new module employs an additional air valve, called the slave valve. The slave slave in vacuum actuated and controlled by the mode Selector vacuum switch. Refer to Fig. 1.

The slave valve is operational (open) in the "HEATER" and "DEF" modes. When open, the valve directs more air through the heater core resulting in higher discharge air temperatures.

Diagnosis for this valve will be found on page 8A-65-0 "Air Delivery" of the 1987 Firenza, Calais, Cutlass Ciera, Deltas, Ninety-Eight Chassis Service Manual.

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.