K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Blower Motor: All Technical Service Bulletins
A/C Blower Motor - Whine or Noise
GMC NUMBER: 90-1B-115
GROUP: 1A Heating and Ventilation
DATE: December, 1990
CORPORATE
NUMBER:061207
SUBJECT:
A/C BLOWER MOTOR NOISE/WHINE
MODELS:
1988-1990 C/K LIGHT DUTY TRUCKS WITH AIR CONDITIONING (RPO C60)
GMC TRUCK RECOMMENDS THAT A COPY OF THIS BULLETIN ALSO BE FILED UNDER SECTION 1B - AIR CONDITIONING
Some 1988-90 C/K trucks may experience a whine or noise from the blower motor. To correct this condition, a blower motor cover has been released to
insulate the noise. Before installing this cover, however, be sure to check the blower motor and fan for proper operation. Compare the complaint noise to
a non-complaint vehicle to determine if the noise is in the "normal" range, or if the motor or fan should be replaced. In addition, the cover will not mask
the noise of the fan rubbing on the "squirrel cage", thus this must be corrected separately.
Figure 1
SERVICE PROCEDURE (Figure 1):
1. Prepare the truck; disconnect the battery cable.
2. Remove the glove box insert.
3. Remove the right lower dash bolt and kick panel for access to the blower motor case.
4. Remove the courtesy lamp.
5. Disconnect the connector from the ECM, and remove the ECM through the glove box.
6. Remove the four screws on the ECM mounting bracket, and remove the ECM mounting bracket.
7. Disconnect the electrical connection at the blower motor.
8. Install the blower motor cover.
