Skylark V6-3100 3.1L VIN M SFI (1996)
Air Door Actuator / Motor: Customer Interest
Instrument Panel Vent - Leaking Air in Heater Modes
File In Section: 1 - HVAC
Bulletin No.: 63-11-09
Date: January, 1997
Air Coming From I/P Vent While In Heater Modes or a Delay Occurs When
Changing to a New Mode Setting (Diagnose/Modify/Replace)
1996-97 Buick Skylark
1996-97 Oldsmobile Achieva
1996-97 Pontiac Grand Am
Some owners may comment on one of the following conditions:
Air is felt coming through the I/P vents while the HVAC system is in "Heater" modes. No air should be felt through the I/P vents in "Heater" modes.
A delay occurs when changing to a new mode setting. The mode typically changes within 1 minute and is accompanied by a hissing sound.
The mode door may not seal tightly to the HVAC module, allowing air to escape through the I/P vents.
The mode switch/valve assembly may not immediately distribute vacuum to the appropriate HVAC module vacuum actuators.
Diagnose the system to determine the condition
Does air come out the I/P vents in ALL "Heater" modes (heat, blend, defrost) but responds correctly in all other modes? If "YES," go to diagnosis for
Condition A (Mode Door Check). If "NO," go to Diagnosis for Condition B (Control Assembly Check).
Mode Door Check
Remove I/P compartment. Refer to Section 8C2 in the Service Manual. Verify vacuum at the mode actuator (yellow label) red hose and observe
door linkage movement. Make corrections if necessary and recheck. If condition was found, corrected, and air now comes out of the correct ducts
based on the mode setting, reinstall the I/P compartment and STOP. If vacuum and door movement are verified and the air still comes out of the
I/P vents in ALL "heater" modes, perform the service procedure listed below then STOP - DO NOT perform Diagnosis for Condition B.
Modify mode door actuator linkage
Remove vacuum lines from mode door actuator.
Remove retaining clip at end of actuator shaft.