GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The A/C condenser fan relay coil receives ignition voltage through the DEF fuse and the relay switch receives battery voltage through the HTR fuse. The powertrain control module (PCM) energizes and de-energizes the relay through the condenser fan relay control circuit. The PCM initiates condenser fan operation in response to an A/C system request, to an engine overheating condition, or to an engine coolant temperature (ECT) sensor malfunction.

Diagnostic Aids

The PCM initiates condenser fan operation when any one of the following conditions are met:

    • The engine coolant temperature (ECT) is 113°C (235°F) or higher. Connect a scan tool in order to determine ECT. Refer to Symptoms - Engine Cooling in Engine Cooling.
    • The PCM detects an ECT sensor malfunction. Refer to the following in Engine Controls 1.6 L:
       -  DTC P0116
       -  DTC P0117
       -  DTC P0118
    • Refer to the following in Engine Controls 2.0 L:
       -  DTC P0116
       -  DTC P0117
       -  DTC P0118
    • Refer to the following in Engine Controls 2.5 L:
       -  DTC P0116
       -  DTC P0117
       -  DTC P0118
    • The A/C system is operating.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

This table assumes that there are no engine overheating concerns and no DTCs set.

1

Did you review the Air Delivery Description and Operation and the Air Temperature Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual

2

  1. Start the engine.
  2. Connect a scan tool and monitor the A/C condenser fan status.
  3. Turn the A/C switch to the OFF position.

Does the A/C condenser fan stop?

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

Go to Step 3

3

Disconnect the A/C condenser fan relay connector.

Does the A/C condenser fan stop?

Go to Step 4

Go to Step 6

4

Test the condenser fan relay for an open condition between terminals 2 and 4. Terminals 2 and 4 are the switch contacts and are normally open.

Are the condenser fan relay contacts open?

Go to Step 5

Go to Step 7

5

Test for a short to ground in the A/C condenser fan relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

6

Repair the short to voltage in the condenser fan supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

--

7

Replace the A/C condenser fan relay. Refer to Condenser Fan Relay Replacement .

Did you complete the replacement?

Go to Step 9

--

8

Replace the PCM. Refer to the following:

    •  Powertrain Control Module Replacement in Engine Controls-1.6 L
    •  Powertrain Control Module Replacement in Engine Controls-2.0 L
    •  Powertrain Control Module Replacement in Engine Controls-2.5 L

Did you complete the replacement?

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3