For 1990-2009 cars

## Cooling Fan Inoperative V6

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

The engine control module (ECM) commands the fans ON in either high speed, medium speed, or low speed, depending on cooling requirements.

#### Low Speed

In low speed operation, the ECM applies ground to the coil side of the following relays with the cooling fan relay 1 control circuit:

• | Cooling Fan Left Low Speed Relay

• | Cooling Fan Right Low Speed Relay

• | Cooling Fan Speed Control Relay

This energizes the relay coils. The low speed cooling fan relays supply power to the appropriate cooling fan motor through an internal fan resistor. The fan speed control relay contacts close and supply a direct ground path for the left cooling fan motor. The right cooling fan motor is connected to a dedicated ground. This results in both fans operating at low speed.

#### Medium Speed

In medium speed operation, the ECM commands the low speed fan relays, and the speed control relay off. The ECM simultaneously commands both of the cooling fan high speed relays on with the cooling fan relay 2 control circuit. The cooling fan motors are supplied power directly from the cooling fan high speed relays. The right cooling fan is connected to a dedicated ground, and operates at high speed. The left cooling fan is supplied a ground through the right cooling fan resistor and fan motor, which is connected to the de-energized cooling fan speed control relay. This results in the right cooling fan operating at a reduced speed.

#### High Speed

In high speed operation, the ECM applies a ground to the coil side of all five cooling fan relays. When energized, the high speed relays apply voltage directly to the cooling fans through the switch side of the relays. The energized cooling fan speed control relay provides a direct ground circuit for the left cooling fan. This arrangement allows each fan to receive full voltage and operate at high speed.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Cooling Fan Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. Verify that DTCs P0480, P0481, P0691, P0692, P0693 or P0694 are not set.

⇒ | If any of the above DTCs are set refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694.

2. Ignition ON, command the appropriate fan relay ON and OFF with a scan tool. Verify that the fans turn ON and OFF when changing between the commanded states.

### Circuit/System Testing

1. Ignition OFF, disconnect all five cooling fan relays.
2. Test for less than 5 Ω between the KR20E cooling fan speed control relay terminal 8 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

Note: The following test must performed on all cooling fan relays.

3. Ignition ON, verify that a test lamp illuminates between each relay switch B+ circuit terminal and ground.

⇒ | If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay switch B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the appropriate cooling fan motor.

4. Ignition OFF, connect a jumper wire between the KR20E cooling fan speed control relay switch terminal 2 and the relay ground circuit terminal 8.

Note: The following test must be performed on both cooling fan low speed relays.

5. Connect a 20 A fused jumper between the cooling fan low speed relay switch B+ circuit terminal 2 and the relay controlled output circuit terminal 8. Ignition ON, verify the cooling fan is activated.

⇒ | If the fan does not activate, test the following conditions and repair as necessary.

• | Relay controlled output circuit for a short to ground or an open/high resistance

• | Open cooling fan resistor

• | Open circuit between the G10L left cooling fan relay and the KR20E cooling fan speed relay

• | Fan ground circuit for an open/high resistance

• | Cooling fan motor

Note: The following test must be performed on both cooling fan high speed relays.

6. Ignition OFF, remove the low speed fan relay jumper wire. Connect a 20 A fused jumper between the cooling fan high speed relay switch B+ circuit terminal 2 and the relay controlled output circuit terminal 8. Ignition ON, verify the cooling fan is activated.

⇒ | If the fan does not activate, test the relay controlled output circuit for a short to ground or an open/high resistance.

7. Ignition OFF, remove the jumper wire from the cooling fan speed control relay terminal 8. Install the jumper wire to the cooling fan speed control relay terminal 5.
8. Ignition ON, verify that the left cooling fan is activated.

⇒ | If the left cooling fan does not activate test the relay controlled output circuit for an open/high resistance.

9. If all circuits test normal, test or replace the relay.

### Component Testing

1. Ignition OFF, disconnect the cooling fan relay.
2. Test for 70-110 Ω between terminals 4 and 6.

⇒ | If the not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 2 and 6

• | 2 and 8

• | 2 and 4

• | 4 and 8

⇒ | If not the specified range, replace the relay.

4. Install a 20 A fused jumper wire between relay terminal 4 and B+. Install a jumper wire between relay terminal 6 and ground. Test for less than 2 Ω between terminals 2 and 8.

⇒ | If greater than the specified range, replace the relay.

Note: This step is only for the KR20E cooling fan speed control relay.

5. Remove the jumper wires. Test for less than 2 Ω between terminals 2 and 5.

⇒ | If greater than the specified range, replace the relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Relay Replacement

• | Engine Coolant Fan Motor Replacement

## Cooling Fan Inoperative LDK with Single Fan

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

The engine cooling fan system is composed of one fan, 5 relays, the engine control module (ECM), and the associated wiring. The fan assembly includes two resistors, which enable the fan to operate at 3 speeds.

In low speed operation, the ECM provides ground to ECM terminal X2 46. The Cooling Fan Relay activates and provides ground to the coils of the Cooling Fan Medium Speed 2 Relay and the Cooling Fan Speed Control Relay. The Cooling Fan Speed Control Relay activates and provides power to the coil of the Cooling Fan High Speed Relay. The Cooling Fan High Speed Relay remains inactive because ECM terminal X2 45 is not grounded. The Cooling Fan Medium Speed 2 Relay provides power to the cooling fan motor through cooling fan terminal 2 and the internal fan resistor.

In medium speed operation, the ECM provides ground to ECM terminal X2 45. The Cooling Fan High Speed Relay remains inactive because power is not provided to the coil from the Cooling Fan Speed Control Relay. The Cooling Fan Medium Speed 1 Relay activates and provides power to the cooling fan motor through cooling fan terminal 3 and the internal fan resistor.

In high speed operation, the ECM provides ground to ECM terminals X2 45 and X2 46. As previously described, power is now provided to both cooling fan terminals 2 and 3. In addition, power and ground are now provided to the coil of the Cooling Fan High Speed Relay. The Cooling Fan High Speed Relay activates and provides power to the cooling fan motor through cooling fan terminal 4.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Cooling Fan Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Verify that DTCs P0480, P0481, P0691, P0692, P0693 and P0694 are not set.

⇒ | If any cooling system DTCs are set, repair the DTC first. Refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694.

2. Command the Fan Relay 1 ON and OFF with a scan tool. The fan should turn ON at low speed and OFF with each command.

⇒ | If the fan does not operate correctly, go to low speed operation malfunction.

3. Command the Fan Relay 2 and 3 ON and OFF with a scan tool. The fan should turn ON at medium speed and OFF with each command.

⇒ | If the fan does not operate correctly, go to medium speed operation malfunction.

4. Command the Fan Relay 1, 2, and 3 ON and OFF with a scan tool. The fan should turn ON at high speed and OFF with each command.

⇒ | If the fan does not operate correctly, go to high speed operation malfunction.

### Circuit/System Testing

Note: The Circuit/System Verification must be performed before the Circuit/System Testing or misdiagnosis may result.

#### Low Speed Malfunction

1. Ignition OFF, disconnect the relays listed below:

• | KR20B Cooling Fan Medium Speed 2 Relay

• | KR20E Cooling Fan Speed Control Relay

• | KR20F Cooling Fan Relay

2. Test for less than 1Ω between the relay controlled output circuit terminal of the KR20F Cooling Fan Relay and ground.

⇒ | If greater than the specified range, test the output circuit for an open/high resistance.

3. Verify that a test lamp illuminates between the relay coil ignition circuit terminal of the KR20B Cooling fan Medium Speed 2 Relay connector and ground.

⇒ | If the test lamp does not illuminate, test the relay coil ignition circuit for an open/high resistance.

4. Verify that a test lamp illuminates between the relay switch B+ circuit terminal of the KR20B Cooling Fan Medium Speed 2 Relay connector and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay controlled output circuit terminals of the relay connectors listed below for a short to ground:

• | KR20A Cooling Fan Medium Speed 1 Relay

• | KR20B Cooling Fan Medium Speed 2 Relay

5. Install a 10A fused jumper wire between the relay coil ignition circuit terminal and the relay coil control circuit terminal of the KR20B Cooling Fan Medium Speed 2 Relay connector.
6. Verify that a test lamp illuminates between the relay switch ignition circuit terminal and the relay controlled output circuit terminal at the KR20F Cooling Fan Relay connector.

⇒ | If the test lamp does not illuminate, test the relay switch ignition circuit terminal at the KR20F Cooling Fan Relay connector for a short to ground or an open/high resistance.

7. Disconnect the harness connector at the G10 Engine Cooling Fan.
8. Test for less than 1.0Ω between the G10 Engine Cooling Fan ground circuit terminal 1 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

9. Connect the harness connector at the G10 Engine Cooling Fan.
10. Connect a 60A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal of the KR20B Cooling fan Medium Speed 2 Relay connector. Verify the cooling fan is activated at low speed.

⇒ | If the cooling fan does not activate at low speed, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the cooling fan.

11. If all circuits test normal, test the relays listed below for correct operation and replace the faulty relay:

• | KR20F Cooling Fan Relay

• | KR20B Cooling Fan Medium Speed 2 Relay

#### Medium Speed Malfunction

1. Ignition OFF, disconnect the KR20A Cooling Fan Medium Speed 1 Relay.
2. Verify that a test lamp illuminates between the relay coil ignition circuit terminal and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

3. Verify that a test lamp illuminates between the relay switch B+ circuit terminal and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

4. Connect a 60A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal. Verify the cooling fan is activated at medium speed.

⇒ | If the cooling fan does not activate at medium speed, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the G10 Engine Cooling Fan.

5. Test for less than 1V between the relay coil control circuit terminal and ground.

⇒ | If more than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, test the KR20E Cooling Fan Speed Control Relay for correct operation. If the relay tests normal, replace the K20 ECM.

6. If all circuits test normal, test or replace the KR20A Cooling Fan Medium Speed 1 Relay.

#### High Speed Malfunction

1. Ignition OFF, disconnect the relays listed below:

• | KR20D Cooling Fan High Speed Relay

• | KR20E Cooling Fan Speed Control Relay

2. Verify that a test lamp illuminates between the relay coil ignition circuit terminal of the KR20E Cooling Fan Speed Control Relay connector and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance.

3. Verify that a test lamp illuminates between the relay switch ignition circuit terminal of the KR20E Cooling Fan Speed Control Relay connector and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance.

4. Install a 10A fused jumper wire between the relay switch ignition circuit terminal and the relay controlled output circuit terminal of the KR20E Cooling Fan Speed Control Relay connector.
5. Verify that a test lamp illuminates between the relay coil ignition circuit terminal of the KR20D Cooling Fan High Speed Relay connector and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit terminal for an open/high resistance.

6. Verify that a test lamp illuminates between the relay switch B+ circuit terminal of the KR20D Cooling Fan High Speed Relay connector and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the G10 Engine Cooling Fan.

7. Connect a 60A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal to the KR20D Cooling Fan High Speed Relay connector. Verify the cooling fan is activated at high speed.

⇒ | If the cooling fan does not activate at high speed, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the G10 Engine Cooling Fan.

8. If all circuits test normal, test the relays listed below for correct operation and replace the faulty relay:

• | KR20E Cooling Fan Speed Control Relay

• | KR20D Cooling Fan High Speed Relay

### Component Testing

1. Ignition OFF, disconnect the cooling fan relay.
2. Test for 70-110Ω between terminals 85 and 86.

⇒ | If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 30 and 86

• | 30 and 87

• | 30 and 85

• | 85 and 87

⇒ | If not the specified range, replace the relay.

4. Test for less than 2Ω between terminals 30 and 87A.

⇒ | If greater than the specified range, replace the relay.

5. Install a 20A fused jumper wire between relay terminal 85 and 12V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2Ω between terminals 30 and 87.

⇒ | If greater than the specified range, replace the relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Relay Replacement

• | Engine Cooling Fan Replacement 37302

## Cooling Fan Inoperative LCD, LBX or LBS

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

#### KR20J Cooling Fan Left High Speed Relay

Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance
--- | --- | --- | --- | --- | ---
Relay Coil Ignition Circuit | P0691 00 | P0691 00 | P0480 00 | -- | --
Relay Switch B+ Circuit | 1 | 1 | 1 | -- | --
Relay Coil Control Circuit | P0691 00 | P0691 00 | P0480 00 | P0692 00 | --
Relay Controlled Output Circuit | 1 | 1 | 1 | 2 | --

1. Low and medium speed fan inoperative without a DTC.
2. Medium speed fan always ON without a DTC.

#### KR20G Cooling Fan Left Low Speed Relay, KR20E Cooling Fan Speed Control Relay and KR20H Cooling Fan Right Low Speed Relay

Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance
--- | --- | --- | --- | --- | ---
Relay Coil Ignition Circuit | P0693 00 | P0693 00 | P0481 00 | -- | --
Relay Switch B+ Circuit | 1 | 1 | 1 | -- | --
Relay Coil Control Circuit | P0693 00 | P0693 00 | P0481 00 | P0694 00 | --
Relay Controlled Output Circuit | 1 | 1 | 1 | 2 | --

1. Fans inoperative without a DTC.
2. Medium speed fan always ON without a DTC.

#### KR20A Cooling Fan Medium Speed Relay

Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance
--- | --- | --- | --- | --- | ---
Relay Coil Ignition Circuit | P0695 00 | P0695 00 | P0482 00 | -- | --
Relay Switch B+ Circuit | 1 | 1 | 1 | -- | --
Relay Coil Control Circuit | P0695 00 | P0695 00 | P0482 00 | P0696 00 | --
Relay Controlled Output Circuit | 1 | 1 | 1 | 2 | --

1. High speed fan inoperative without a DTC.
2. High speed fan always ON without a DTC.

### Circuit/System Description

The engine control module (ECM) commands the fans ON in either high speed, medium speed, or low speed, depending on cooling requirements.

#### Low Speed

In low speed operation, the ECM applies ground to the coil side of the following relays with the cooling fan relay 1 control circuit:

• | Cooling Fan Left Low Speed Relay

• | Cooling Fan Right Low Speed Relay

• | Cooling Fan Speed Control Relay

This energizes the relay coils. The low speed cooling fan relays supply power to the appropriate cooling fan motor through an internal fan resistor. The fan speed control relay contacts close and supply a direct ground path for the left cooling fan motor. The right cooling fan motor is connected to a dedicated ground. This results in both fans operating at low speed.

#### Medium Speed

In medium speed operation, the ECM commands the low speed fan relays, and the speed control relay off. The ECM simultaneously commands both of the cooling fan high speed relays on with the cooling fan relay 2 control circuit. The cooling fan motors are supplied power directly from the cooling fan high speed relays. The right cooling fan is connected to a dedicated ground, and operates at high speed. The left cooling fan is supplied a ground through the right cooling fan resistor and fan motor, which is connected to the de-energized cooling fan speed control relay. This results in the right cooling fan operating at a reduced speed.

#### High Speed

In high speed operation, the ECM applies a ground to the coil side of all five cooling fan relays. When energized, the high speed relays apply voltage directly to the cooling fans through the switch side of the relays. The energized cooling fan speed control relay provides a direct ground circuit for the left cooling fan. This arrangement allows each fan to receive full voltage and operate at high speed.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Cooling Fan Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. Verify that DTCs P0480, P0481, P0482, P0691, P0692, P0693, P0694, P0695 ore P0696 are not set.

⇒ | If any of the above DTCs are set refer to Diagnostic Trouble Code (DTC) List - Vehicle

2. Ignition ON, command the appropriate fan relay ON and OFF with a scan tool. Verify that the fans turn ON and OFF when changing between the commanded states.

### Circuit/System Testing

1. Ignition OFF, disconnect all five cooling fan relays.
2. Test for less than 5 Ω between the KR20E Cooling Fan Speed Control Relay terminal 8 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

Note: The following test must performed on all cooling fan relays.

3. Ignition ON, verify that a test lamp illuminates between each relay switch B+ circuit terminal and ground.

⇒ | If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay switch B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the appropriate cooling fan motor.

4. Ignition OFF, connect a jumper wire between the KR20E Cooling Fan Speed Control Relay terminal 2 and the relay ground circuit terminal 8.

Note: The following test must be performed on both cooling fan low speed relays.

5. Connect a 20 A fused jumper between the cooling fan low speed relay switch B+ circuit terminal 2 and the relay controlled output circuit terminal 8. Ignition ON, verify the cooling fan is activated.

⇒ | If the fan does not activate, test the following conditions and repair as necessary.

• | Relay controlled output circuit for a short to ground or an open/high resistance

• | Open cooling fan resistor

• | Open circuit between the G10L Cooling Fan Motor - Left terminal 3 and the KR20E Cooling Fan Speed Control Relay terminal 2

• | Fan ground circuit for an open/high resistance

• | Cooling fan motor

Note: The following test must be performed on both cooling fan high speed relays.

6. Ignition OFF, remove the low speed fan relay jumper wire. Connect a 20 A fused jumper between the cooling fan high speed relay switch B+ circuit terminal 2 and the relay controlled output circuit terminal 8. Ignition ON, verify the cooling fan is activated.

⇒ | If the fan does not activate, test the relay controlled output circuit for a short to ground or an open/high resistance.

7. Ignition ON, verify that the left cooling fan is activated.

⇒ | If the left cooling fan does not activate test the relay controlled output circuit for an open/high resistance.

8. If all circuits test normal, test or replace the relay.

### Component Testing

#### Relay Test

1. Ignition OFF, disconnect the cooling fan relay.
2. Test for 70-110 Ω between terminals 4 and 6.

⇒ | If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 2 and 6

• | 2 and 8

• | 2 and 4

• | 4 and 8

⇒ | If not the specified value, replace the relay.

4. Install a 20 A fused jumper wire between relay terminal 4 and B+. Install a jumper wire between relay terminal 6 and ground. Test for less than 2 Ω between terminals 2 and 8.

⇒ | If greater than the specified range, replace the relay.

Note: This step is only for the KR20E cooling fan speed control relay.

5. Remove the jumper wires. Test for less than 2 Ω between terminals 2 and 5.

⇒ | If greater than the specified range, replace the relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | LINK 22835

• | Engine Coolant Fan Motor Replacement

## Cooling Fan Inoperative LDK with Dual Fan

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

The engine control module (ECM) commands the fans ON in either high speed, medium speed, or low speed, depending on cooling requirements.

#### Low Speed

In low speed operation, the ECM applies ground to the coil side of the following relays with the cooling fan relay 1 control circuit:

• | Cooling Fan Left Low Speed Relay

• | Cooling Fan Right Low Speed Relay

• | Cooling Fan Speed Control Relay

This energizes the relay coils. The low speed cooling fan relays supply power to the appropriate cooling fan motor through an internal fan resistor. The fan speed control relay contacts close and supply a direct ground path for the left cooling fan motor. The right cooling fan motor is connected to a dedicated ground. This results in both fans operating at low speed.

#### Medium Speed

In medium speed operation, the ECM commands the low speed fan relays, and the speed control relay off. The ECM simultaneously commands both of the cooling fan high speed relays on with the cooling fan relay 2 control circuit. The cooling fan motors are supplied power directly from the cooling fan high speed relays. The right cooling fan is connected to a dedicated ground, and operates at high speed. The left cooling fan is supplied a ground through the right cooling fan resistor and fan motor, which is connected to the de-energized cooling fan speed control relay. This results in the left cooling fan operating at a reduced speed.

#### High Speed

In high speed operation, the ECM applies a ground to the coil side of all five cooling fan relays. When energized, the high speed relays apply voltage directly to the cooling fans through the switch side of the relays. The energized cooling fan speed control relay provides a direct ground circuit for the left cooling fan. This arrangement allows each fan to receive full voltage and operate at high speed.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Cooling Fan Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. Verify that DTCs P0480, P0481, P0691, P0692, P0693 or P0694 are not set.

⇒ | If any of the above DTCs are set refer to DTC P0480, P0481, P0691, P0692, P0693, or P0694.

2. Ignition ON, command the appropriate fan relay ON and OFF with a scan tool. Verify that the fans turn ON and OFF when changing between the commanded states.

### Circuit/System Testing

1. Ignition OFF, disconnect all five cooling fan relays.
2. Test for less than 5 Ω between the KR20E cooling fan speed control relay terminal 8 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

Note: The following test must performed on all cooling fan relays.

3. Ignition ON, verify that a test lamp illuminates between each relay switch B+ circuit terminal and ground.

⇒ | If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay switch B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the appropriate cooling fan motor.

4. Ignition OFF, connect a jumper wire between the KR20E cooling fan speed control relay switch terminal 2 and the relay ground circuit terminal 8.

Note: The following test must be performed on both cooling fan low speed relays.

5. Connect a 20 A fused jumper between the cooling fan low speed relay switch B+ circuit terminal 2 and the relay controlled output circuit terminal 8. Ignition ON, verify the cooling fan is activated.

⇒ | If the fan does not activate, test the following conditions and repair as necessary.

• | Relay controlled output circuit for a short to ground or an open/high resistance

• | Open cooling fan resistor

• | Open circuit between the G10L left cooling fan relay and the KR20E cooling fan speed relay

• | Fan ground circuit for an open/high resistance

• | Cooling fan motor

Note: The following test must be performed on both cooling fan high speed relays.

6. Ignition OFF, remove the low speed fan relay jumper wire. Connect a 20 A fused jumper between the cooling fan high speed relay switch B+ circuit terminal 2 and the relay controlled output circuit terminal 8. Ignition ON, verify the cooling fan is activated.

⇒ | If the fan does not activate, test the relay controlled output circuit for a short to ground or an open/high resistance.

7. Ignition OFF, remove the jumper wire from the cooling fan speed control relay terminal 8. Install the jumper wire to the cooling fan speed control relay terminal 5.
8. Ignition ON, verify that the left cooling fan is activated.

⇒ | If the left cooling fan does not activate test the relay controlled output circuit for an open/high resistance.

9. If all circuits test normal, test or replace the relay.

### Component Testing

1. Ignition OFF, disconnect the cooling fan relay.
2. Test for 70-110 Ω between terminals 4 and 6.

⇒ | If the not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 2 and 6

• | 2 and 8

• | 2 and 4

• | 4 and 8

⇒ | If not the specified range, replace the relay.

4. Install a 20 A fused jumper wire between relay terminal 4 and B+. Install a jumper wire between relay terminal 6 and ground. Test for less than 2 Ω between terminals 2 and 8.

⇒ | If greater than the specified range, replace the relay.

Note: This step is only for the KR20E cooling fan speed control relay.

5. Remove the jumper wires. Test for less than 2 Ω between terminals 2 and 5.

⇒ | If greater than the specified range, replace the relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Relay Replacement

• | Engine Coolant Fan Motor Replacement