Loss of Airflow From A/C Outlets after Extended Periods of Highway Driving #98-T-10A - (Jan 13, 2003)

1994-1999 Saturns equipped with R-134a air conditioning.

Condition:

After extended periods of highway driving, some customers may notice a loss of airflow from the A/C outlets.

Cause:

A/C compressor suction set point may be low for some customer usage and driving patterns, resulting in evaporator freeze after extended periods of highway driving.

Correction:

Adjust A/C compressor set point using the following procedure.

Procedure:

Notice

This procedure should never be repeated on the same A/C compressor. If condition is not corrected by this bulletin, refer to the diagnostic flow chart in the appropriate year "HVAC Service Manual."

1. Confirm with customer that A/C system functions normally in all conditions, except extended driving at highway speeds.
• If A/C system does not function normally at any other condition , refer to the A/C system diagnostic flow chart in the appropriate year "HVAC Service Manual."
• If A/C system Functions normally during all other conditions , proceed to the next step.





Important

Engine does not need to be running for the A/C compressor set point adjustment.

2. Locate the set screw on the rear head of the A/C compressor. The set screw will be covered with either a solid silver label or a silver label with the words: CAUTION! DO NOT REMOVE CONTENTS UNDER PRESSURE.

Notice

Do not remove this label.






Caution

Be careful to keep hands clear of the engine cooling fan. The engine cooling fan may operate unexpectedly.

Notice

If the silver label has been broken, or an orange replacement label is present, DO NOT continue with this procedure. Additional adjustment of the set screw could result in reduced A/C system performance at higher ambient temperatures.

3. Determine where the large slot in the set screw is located. The slot can be felt through the label with a screwdriver.
1. Using a utility knife, cut through the label for access to the slot screw (1).
2. Using a permanent ink marker, make a mark on the A/C compressor to indicate the current position of the set screw in relation to the compressor rear head (2).





Caution

Do not turn the set screw on the back of the A/C compressor counterclockwise. The A/C system is under pressure and turning the set screw counterclockwise could cause the set screw and/or hot refrigerant/oil mixture to be discharged under pressure. The refrigerant/oil mixture can cause burns and/or bodily injury.

Notice

Do not turn the set screw more than 1/4 turn clockwise. Adjusting the set point changes the pressure at which the A/C compressor goes to minimum displacement. Increasing the adjustment beyond 1/4 turn clockwise will not make the system colder and could reduce A/C system performance at higher ambient temperatures.

4. Using a large-blade screwdriver, turn the set screw 1/4 turn clockwise as viewed from the rear of the compressor.
5. Using a clean shop towel, wipe the surface area where the silver label is located. Make certain there is no debris or oil present.

Notice

To prevent the A/C compressor set screw from being adjusted again, the orange A/C refrigerant caution label P/N 21031284 must be installed over the old silver label.

6. Install a new orange A/C refrigerant caution label P/N 21031284 over the old silver label that was cut in step 3a.
7. Start the engine and inspect that the A/C system is functioning normally.

Parts Requirements:

P/N 21031284 Label -- A/C Refrig Caution.

Claim Information

To receive credit for this repair during the warranty period, submit a claim through the

Saturn Dealer System as follows:

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer".  They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle.  Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely.  If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition.  See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation.  All Rights Reserved.