NO LOW/MEDIUM A/C-HEATER BLOWER SPEEDS (REPAIR INFO)

NO LOW OR NO LOW AND MEDIUM A/C-HEATER BLOWER SPEED

Vehicles Affected: 1988 C/K MODELS WITH A/C (RPO C60)

A loose evaporator screen or loose wire in the screen may contact and short the low and medium speed resistor in the A/C-heater module on some subject vehicles. This could result in a lack of low or medium blower motor speeds.

To repair this condition:

1. Disconnect negative battery cable.

2. Remove glove box from dash.

3. Remove the two screws securing bracket bar to heater module and set bracket bar aside.

4. Remove resistor (See Service Manual X-8731, Page 1B.27 for illustration of resistor) located on top of heater module.

5. Check for loose evaporator screen wire which may contact resistor. Remove if present.

6. Glue or epoxy the loose screen to the top of the evaporator core. Hold the screen against the core and liberally apple DAP Contact Cement or equivalent along top of screen or press RTV through screen to top of core.

7. Replace resistor, Part Number 15551633.

8. Reinstall bracket bar and glove box and reconnect negative battery cable.

Use the most applicable labour operation from the Canadian Labour Time Guide.

Screens have been secured to the evaporator coil by means of a plastic prong retainer in production starting with the following VIN breakpoints:

Assembly Plant VIN Breakpoints -------------- --------------- Pontiac JE515486 (GMC) JE145735 (Chevrolet) Fort Wayne JZ519401 (GMC) JZ157778 (Chevrolet) Oshawa J1529931 (GMC) J1180739 (Chevrolet)

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.