Had to replace my battery, now the A/C does not work. It blows hot air (heater) on the driver side and outside air on the passenger side. Read that it could be one of the seven relays within the A/C wiring system. Also that the is a relay by the gas pedel which might be the culprit.
Is there a location diagram of all the relays associated with the A/C? What does the relay by the gas pedal look like, I pulled what I thought was the relay but it was 4'' x 6'', a little big for a relay.
Any help would be appreciated since it's 113.

 

Try taking the batt cables back off and reinstalling. The a/c actuators have been known to forget there positioning and if undoing the cables doesn't solve your issue you may have to pay someone to do a relearn.

 

Wasn't there a TSB about doing a relearn on 03- up systems to get the system to function properly after disconnecting the battery???

 

If they don't relearn you'll need to replace them. Happens all the time.

 

What do you have to replace? The relays?

 

I believe he is referring to the the blend door motor.

 

Bulletin No.: 02-01-39-005

Date: September, 2002

TECHNICAL

Subject:
HVAC System Inoperative For A Drive Cycle, Poor HVAC System Performance In High Ambient Temperatures (Update HVAC Control Module Software)

Models:
2002-2003 Chevrolet TrailBlazer, TrailBlazer EXT
2002-2003 GMC Envoy, Envoy XL
2002-2003 Oldsmobile Bravada

Condition

Some customers may comment about no cold air from the heating, ventilation and air conditioning (HVAC) system during a drive cycle. This concern may occur at any time during the drive cycle and at any temperature setting. The HVAC system operation returns to normal after the vehicle has been keyed to off and restarted. This concern is intermittent and most likely to occur on hot days. This concern may be found on vehicles equipped with manual (CJ2) and automatic (CJ3) HVAC systems. Other customers may comment about poor HVAC system performance in high ambient temperature conditions. This concern may be present in automatic (CJ2) HVAC systems only. An HVAC control module software update was put into all production vehicles beginning in September 2002. Vehicles built in September 2002 and earlier may need this software update.

Correction

Update the HVAC control module using software available through GM Access beginning September 9, 2002. The update will be fully available October 7, 2002 to all dealers on TIS 2000 CD version 10. This software update addresses both the intermittent no cooling and the poor performance concerns. If the software update does not correct the concerns, perform the HVAC Diagnostic System Check and repair as necessary. If the HVAC control module is replaced with a pan from GMSPO, make sure the module has the latest software update. The module may need to be updated even though it is a new part.

 

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.

Park the vehicle inside or in the shade.
Open the windows in order to ventilate the interior of the vehicle.
If the A/C system was operating, allow the A/C system to equalize.
Turn OFF the ignition.
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.


Notice
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 O-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 before servicing.

Install the J 43600 ACR 2000 Air Conditioning Service Center.

Important
The ambient temperature must be at least 16°C (60°F) .
Do not induce additional air flow across the front of the vehicle during the test.

Record the ambient temperature displayed on the J 43600.
Record readings of the low and high side STATIC pressures. The pressures should be within the specifications listed below.
Above 16°C (60°F): 345 kPa (50 psi)
Above 24°C (75°F): 483 kPa (70 psi)
Above 33°C (90°F): 690 kPa (100 psi)
If the static pressures are within specification, continue with Step 12.
If the static pressures are NOT within specifications, refer to Leak Testing (SI Document ID# 1141201).
Apply the parking brake.
Place the transaxle/transmission in PARK.
Start the engine.
Turn on the A/C system.
Inspect the A/C compressor to see if it is operating properly.



If the compressor is not operating as designed, tap on the low pressure cycling switch (2) with a small hand tool. The compressor should start operating correctly.
If the compressor does not operate correctly after tapping on the low pressure cycling switch (2), disconnect the switch and jumper the lower pressure cycling switch connector with a fused jumper. If the compressor still does not operate properly, refer to HVAC Compressor Clutch Does Not Engage diagnostic in SI.

Important
DO NOT USE A/C low pressure cycling switch, P/N 15035084 on the vehicles listed above.


If the compressor does operate correctly after tapping on the switch or jumping the low pressure cycling switch connector, replace the low pressure cycling switch (2), P/N 89040362. Refer to Air Conditioning (A/C) Low Pressure Switch Replacement in SI.
Perform the Air Conditioning (A/C) System Performance Test in SI.
Disconnect the J 43600 ACR 2000 Air Conditioning Service Center.
Remove the fender covers and close the hood.
Parts Information

Important
Only a small quantity of parts are available. Please DO NOT order for stock only.


Part Number
Description
Qty

89040362
Switch, Pressure Cycling
1


Parts are currently available from GMSPO.

Warranty Information
Labor Operation
Description
Labor Time

D1180
Switch, Pressure Cycling - Replace
Use published labor operation time

 

Thank you for all the information. I disconnected the battaery for 20 minutes and the A/C works. I was looking at $$$$$, thanks again.