Trans Sport V6-191 3.1L (1990)
Housing Assembly HVAC: All Technical Service Bulletins
Antenna Mast - Whistle Noise At Highway Speeds
Bulletin Number:
91-1-10A
Reference Number:
131103R
Publish Date:
6/92
Subject:
WHISTLE NOISE AT HIGHWAY SPEEDS AND/OR CERTAIN HEATER CONTROL POSITIONS (DIAGNOSIS PROCEDURE)
Models Affected:
1990-91 TRANS SPORT MODELS
THIS BULLETIN UPDATE RELEASES A NEW ANTENNA MAST FOR "DIAGNOSIS" -STEP 1, ALONG WITH PART AVAILABILITY AND
WARRANTY INFORMATION FOR ANTENNA. A SOURCE DISCLAIMER LISTED IN CORRECTION #1 WAS ALSO ADDED. THIS
BULLETIN CANCELS AND REPLACES BULLETIN 91-1-10 ISSUED 4/91. PLEASE DISCARD BULLETIN 91-1-10.
Some customers of 1990-91 Trans Sport models may comment about whistling sounds either while driving the vehicle at highway speeds and/or with the
heater controls in certain positions.
Conditions:
1.Constant whistle noise while driving at highway speeds or while driving with heater controls in any position EXCEPT MAX.
2.
Whistle noises with the heater controls in the DEFROST OR MIX modes OR: with the control in the HEAT, MIX or DEFROST modes with the
TEMP LEVER from 0 to 1/4 position and in 3/4 position (opposite the MIX button).
Causes:
1. Speed related noises are most likely due to high velocity air passing through the cowl panel grill, that may be mispositioned.
2.
Noises with the heater controls in certain positions may be due to EITHER air leakage past the hinge area of the defroster door OR:
air passing through the narrow opening between the temperature door baffle and the outside edge of the slave door.
Diagnosis:
May be performed by road testing the vehicle and having a 10 mm wrench in your possession OR by testing the Heater and A/C system with the controls
set in positions as noted in the condition sections above.
1.
Road test the vehicle at speeds between 30 and 55 MPH. Note any noises present and pull off the road into a safe parking area. Using the 10mm
wrench, remove the antenna mast, retest the vehicle as before and note any change in noise.
- If the noise changed and no whistle noise is heard, the condition is antenna related. Replace the antenna mast with
P/N 10220990.
- If the noise DID NOT CHANGE, perform Correction #1 only.
Part Availability:
Parts are currently available from GMSPO.
Labor Operation Number:
R0220
Labor Time
: 0.2 Hr.
2.
Whistle noises with controls in certain positions may be diagnosed by parking the vehicle in a QUIET area and noting noises while the controls are
positioned as indicated in the condition sections above.
For noises noted with controls in DEFROST or MIX or DEFROST modes and TEMP LEVER from 0 to 1/4 position and 3/4 position perform
correction #3.
