B3000 2WD V6-3.0L OHV (1994)
Housing Assembly HVAC: Customer Interest
Blower Motor - Whistle Noise on HIGH
Bulletin No.: 007/95
Issued: 2/15/95
Revised:
Category
S
Applicable Model/s
1994 Navajo
1994 B-Series
Subject:
WHISTLE NOISE WITH BLOWER MOTOR ON "HI"
APPLICABLE MODELS/VINS
1994 Navajo and B-Series Trucks built before 12/22/93.
NOTE:
The vehicle build date is stamped on the radiator support.
DESCRIPTION
A whistle type of noise may be heard from the dash area. The noise occurs when the fan speed is set on "HI" and the temperature control is in the full
"WARM" mode.
The whistle is not heard when the temperature control is switched to the "COOL" mode.
The whistle may be caused by excessive clearance between the two (2) plenum case halves where the blend door is positioned when the full "WARM"
mode is selected.
Customers complaining of a whistle should have any seam leaks in the plenum case sealed. Follow the instructions in this bulletin to seal the plenum case
and eliminate the whistle noise.
REPAIR PROCEDURE
1.
Verify if the whistle is caused by a seam leak in the plenum and not a body seal leak.
^
Start engine, set blower speed at "HI" and temperature control in the full "WARM" mode.
^
Confirm whistle exists at plenum case. If whistle is heard, proceed to step 2. If "whistle is not heard, road test vehicle to determine the source
of the whistle.
2.
Roll window down at least 1 inch (25.4 mm)
^
If the whistle continues, a plenum seal leak exists. Proceed to Step 3.
^
If whistle is not heard, then the source of the whistle is not the plenum. The source is a body leak and should be located using body leak
detection methods
3.
Remove the plenum.
4.
Locate all seal leaks and seal with strip caulk (or equivalent).
5.
Install plenum and verify repair
PARTS INFORMATION
Part Number
Description
08578
3M Strip Caulk
NOTE:
