HVAC Compressor Clutch Does Not Engage. Chevrolet Impala 2002

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2002 🢒 Impala 🢒 Engine 🢒 Engine Cooling 🢒 HVAC Compressor Clutch Does Not Engage

Test Description

The numbers below refer to the step numbers on the diagnostic table.

The A/C compressor relay output is disabled if engine coolant temperature is above 121°C (250°F). The engine coolant indicator will illuminate at this temperature.

The HVAC control module is inoperative when the HVAC control unit does not respond to any operator control request to enable the A/C compressor. The blower motor may still operate independent of the A/C controls.

Step

Action

Values

Yes

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The A/C compressor clutch will not engage when an A/C request has been made and a Powertrain DTC has not been set.

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

Start the engine.
Observe the coolant temperature indicator.

Is the engine coolant temperature indicator illuminated?

Go to Engine Coolant Temperature Indicator Always On in Engine Cooling

Go to Step 3

Important: For A/C compressor operation, ambient air temperature must be above 3°C (36°F).

Start the engine.
Place the blower motor switch in the maximum speed position.
Place the A/C switch in the ON position.
Place the air temperature switch in the coldest position.

Does the A/C compressor operate?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 4

Park the vehicle in the shade.
Open the windows in order to ventilate the interior of the vehicle.
If the A/C system was operating, then allow the A/C system to equalize for approximately 2 minutes.
Ensure that the ignition key is in the OFF position.
Install the J 43600 ACR 2000 Air Conditioning Service Center.
Record the ambient air temperature at the vehicle.
Record readings of the low and high side STATIC pressures.
Compare the low and high side pressure values with the allowable limits for the recorded ambient air temperature. Refer to Air Conditioning (A/C) System Performance Test in Heating, Ventilation and Air Conditioning.

Are the low and high side pressure values within the allowable limits for the recorded ambient air temperature, and within 103 kPa (15 psi) of each other?

Go to Step 5

Go to Leak Testing

Turn ON the ignition, with the engine OFF.
With a scan tool, observe the A/C High Side Pressure parameter in the Powertrain Control Module engine data 2 list.
Compare the A/C high side pressure on the scan tool to the high side pressure value on the ACR 2000.

Are the high side pressure values within 103 kPa (15 psi) of each other?

Go to Step 6

Go to Step 21

Is the HVAC control module inoperative?

Go to Step 10

Go to Step 7

Start the engine.
With a scan tool, observe the A/C Request Signal parameter in the Powertrain Control Module engine data 2 list.
Place the blower motor switch in the maximum speed position.
Place the A/C switch in the ON position.

Does the scan tool indicate that the A/C request parameter is YES?

Go to Step 8

Go to Step 13

With a scan tool, observe the A/C Relay Command parameter in the Powertrain Control Module Engine Data 2 list.

Does the scan tool indicate that the A/C Commanded parameter is ON?

Go to Step 9

Go to Step 31

With a scan tool, command the A/C compressor clutch relay ON and OFF.

Does the A/C compressor clutch relay turn ON and OFF with each command?

Go to Step 14

Go to Step 16

Test the ignition 3 voltage circuit of the HVAC control module for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?