A/C - Windows Fog Up After Selecting DEFOG Mode

File In Section: 01 - HVAC

Bulletin No.: 01-01-38-012

Date: November, 2001

TECHNICAL

Subject:
"Flash" Fogging Occurs When DEFOG Is Selected In Cold, Moist Conditions (Replace Heater & A/C Control Assembly)

Models:
2000-2002 Pontiac Bonneville Built Prior to VIN Breakpoint 24130170 With RPO C67

Condition

Some customers may comment that after selecting the DEFOG mode on the Standard (Manual) Climate Control System, the windows will suddenly fog up. Depending on where the temperature selector is placed and the outside ambient conditions (temperature and humidity), there can be as much as a 10°C (50°F) difference between the defroster and heater duct discharge air temperature.

Cause

This condition may be due to air that is normally routed through the heater core being allowed to bypass the heater core. Most of the air that is allowed to bypass the heater core, under these circumstances, is routed upward to the defroster vents.

Correction

Modifications have been made to the Heater and Air Conditioning Control Assembly. Replace the HTR & A/C Control Assembly. Refer to Control Assembly Replacement in the HVAC System-Manual sub-section of the Service Manual.





Parts Information

Parts are currently available from GMSPO.

Warranty Information





For vehicles repaired under warranty, use table shown.





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