C 1500 Truck 2WD V8-454 7.4L (1990)
Blower Motor: All Technical Service Bulletins
A/C Blower Motor - Whine or Noise
Number: 90-398-1A
Section: 1A
Date: January 1991
Corporate Bulletin No.: 061207
Subject:
AIR CONDITIONING BLOWER MOTOR NOISE
Model and Year:
1988-90 C/K TRUCKS WITH AIR CONDITIONING (RPO C60)
TO: ALL CHEVROLET DEALERS
IT IS RECOMMENDED 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.