K 1500 Truck 4WD V8-4.8L VIN V (2003)
Low Pressure Sensor / Switch: Customer Interest
A/C - Intermittently Inoperative/Blows Warm Air
Bulletin No.: 03-01-39-007
Date: May 29, 2003
TECHNICAL
Subject:
Air Conditioning (A/C) Inoperative/Intermittent, A/C Blows Warm Air (Replace A/C Low Pressure Cycling Switch)
Models:
2003 Cadillac Escalade, Escalade EXT, Escalade ESV
2002-2003 Chevrolet TrailBlazer, TrailBlazer EXT
2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2002-2003 GMC Envoy, Envoy XL
2003 GMC Sierra, Yukon, Yukon XL
2002-2003 Oldsmobile Bravada
2003 HUMMER H2
Condition
Some customers may comment that the A/C system is intermittently inoperative or blows warm air.
Cause
An intermittent inoperative (open) A/C low pressure cycling switch may be the cause. This is an intermittent condition and temperatures may play a
critical role if the vehicle is in the failed mode or operating as designed.
Correction
Follow the diagnosis and service procedure below to correct this condition.
1.
Park the vehicle inside or in the shade.
2.
Open the windows in order to ventilate the interior of the vehicle.
3.
If the A/C system was operating, allow the A/C system to equalize.
4.
Turn OFF the ignition.
5.
Open the hood and install fender covers.
Caution:
^
Avoid breathing the A/C Refrigerant 134a (R-134a) and the lubricant vapor or the mist. Exposure may irritate the eyes, nose, and throat.
Work in a well ventilated area. In order to remove R-134a from the A/C system, use service equipment that is certified to meet the
requirements of SAE J 2210 (R-134a recycling equipment). If an accidental system discharge occurs, ventilate the work area before
continuing service. Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
^
For personal protection, goggles and gloves should be worn and a clean cloth wrapped around fittings, valves, and connections when doing
work that includes opening the refrigerant system. If R-134a comes in contact with any part of the body severe frostbite and personal injury
can result. The exposed area should be flushed immediately with cold water and prompt medical help should be obtained.
Note:
^
R-134a is the only approved refrigerant for use in this vehicle. The use of any other refrigerant may result in poor system performance or
component failure.
^
To avoid system damage use only R-134a dedicated tools when servicing the A/C system.
^
Use only Polyalkylene Glycol Synthetic Refrigerant Oil (PAG) for internal circulation through the R-134a A/C system and only 525
viscosity mineral oil on fitting threads and 0-rings. If lubricants other than those specified are used, compressor failure and/or fitting
seizure may result.
^
R-12 refrigerant and R-134a refrigerant must never be mixed, even in the smallest of amounts, as they are incompatible with each other. If
the refrigerants are mixed, compressor failure is likely to occur. Refer to the manufacturer instructions included with the service equipment
