Electric Cooling Fans Buick LeSabre VIII

DESCRIPTION & OPERATION

ELECTRIC COOLING FAN CONTROL

The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a Series/Parallel (S/P) configuration that allows the Powertrain Control Module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage from the underhood fuse block. The ground path is provided at G103.

During low speed operation, the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the cooling fan 1 fuse through the cooling fan motor supply voltage circuit to the right cooling fan. The ground path for the right cooling fan is through the cooling fan S/P relay and the left cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the PCM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM supplies a ground path for the cooling fan 2 relay and the cooling fan S/P relay through the high speed cooling fan relay control circuit. This energizes the cooling fan S/P relay coil, closes the relay contacts, and provides a ground path for the right cooling fan. At the same time the cooling fan 2 relay coil is energized closing the relay contacts and provides battery positive voltage from the cooling fan 2 fuse on the cooling fan motor supply voltage circuit to the left cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed. The PCM commands the low speed fans ON under the following conditions

1. The engine coolant temperature exceeds approximately 223°F (106°C).
2. The A/C refrigerant pressure exceeds 190 psi (1310 kPa).
3. The vehicle is shut off when the engine coolant temperature is greater than 244°F (118°C) and system voltage is more than 12 volts. The fans will stay ON for approximately 3 minutes.

The PCM commands High Speed Fans on under the following conditions

1. The engine coolant temperature reaches 234°F (112°C).
2. The A/C refrigerant pressure exceeds 237 psi (1634 kPa).

PRELIMINARY INFORMATION

This article contains only the text required to test electric cooling fans. Other diagnostic information may be referenced while performing electric cooling fan diagnosis. See appropriate ENGINE PERFORMANCE articles for complete information on engine control systems.

To help save diagnostic time, always check for blown fuses or fusible links before proceeding with any testing. If fuses are blown, locate and repair short circuit before replacing fuses. See FUSES & CIRCUIT BREAKERS article in ELECTRICAL. Ensure all related relay and wire harness connections are clean and tight. Repair as necessary. See WIRING DIAGRAMS for component, terminal and wire color identification.

DIAGNOSTIC STARTING POINT - ENGINE COOLING

Begin the system diagnosis with the DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING under SELF-DIAGNOSTICS. The Diagnostic System Check will provide the following information

1. The identification of the control modules which command the system.
2. The ability of the control modules to communicate through the serial data circuit.
3. The identification of any stored Diagnostic Trouble Codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

SYMPTOMS - ENGINE COOLING

Review the system operation in order to familiarize yourself with the system functions. See DESCRIPTION & OPERATION .

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Cooling System.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Inspect the surge tank reservoir for the proper coolant level.

Intermittents

Intermittent faulty electrical connections or wiring may be the cause of intermittent conditions. Check for loose, bent or corroded terminals and terminal tension. Check for cut, bare or pinched wiring. Simulate the condition that is potentially causing the intermittent connection, either by wiggling the connections or the wiring, test driving or performing other operations while observing scan tool, DVOM or other testing equipment.

Symptom List

1. «ENGINE COOLANT TEMPERATURE INDICATOR ALWAYS ON»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__engine-coolant-temperature-indicator-always-on) under SYSTEM TESTING.
2. «COOLING FAN ALWAYS ON»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__cooling-fan-always-on) under SYSTEM TESTING.
3. «COOLING FAN INOPERATIVE»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__cooling-fan-inoperative) under SYSTEM TESTING.
4. «ENGINE OVERHEATING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__engine-overheating) under SYSTEM TESTING.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING

1. Install a scan tool. Does the scan tool power up? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article under ACCESSORIES & EQUIPMENT. NOTE: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
2. Turn ignition on, with engine off. Attempt to establish communication with the following control modules: Instrument Cluster Powertrain Control Module Does the scan tool communicate with the control modules? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article under ACCESSORIES & EQUIPMENT. NOTE: Determine if the Instrument Cluster or Powertrain Control Modules have set DTCs which may affect Engine Cooling operation are present.
3. Select the POWERTRAIN CONTROL MODULE display DTCs function on the scan tool. Does the scan tool display any DTCs? If so, go to next step. If not, go to «SYMPTOMS - ENGINE COOLING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__symptoms-engine-cooling) under TROUBLE SHOOTING. NOTE: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
4. Does the scan tool display any DTCs which begin with a "U"? If so, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article under ACCESSORIES & EQUIPMENT. If not, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-trouble-code-definitions) .

Circuit Description

Battery positive voltage is supplied to the cooling fan 1 relay from the cooling fan 1 fuse. The Powertrain Control Module (PCM) controls the cooling fan 1 relay by grounding the low speed cooling fan relay control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component on, the voltage potential of the control circuit should be low (near zero volts). When the PCM is commanding the control circuit to a component off, the voltage potential of the circuit should be high (near battery voltage). If the fault detection circuit senses a voltage other than what is expected, the DTC will set. The PCM will monitor the control circuit for the following

1. A short to ground.
2. A short to voltage.
3. An open circuit.
4. An open relay coil.
5. An internally shorted or excessively low resistance relay coil.

When the PCM detects any of the above conditions, the DTC will set and the affected driver will be disabled.

Conditions for Running the DTC

1. The ignition is ON.
2. System voltage is between 9-18 volts.

Conditions for Setting the DTC

1. An improper voltage level has been detected on the low speed cooling fan relay control circuit.
2. The above conditions are present for at least 30 seconds.

Action Taken When the DTC Sets

1. The PCM will illuminate the Malfunction Indicator Light (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
2. The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
3. A history DTC is stored.

Conditions for Clearing the MIL/DTC

1. The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
2. The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. The DTC can be cleared by using the scan tool CLEAR DTC INFORMATION function.

Diagnostic Aids

If the condition is not present, see INTERMITTENTS in SYMPTOMS - ENGINE COOLING under TROUBLE SHOOTING. Review the Freeze/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

Testing

1. Did you perform the ENGINE COOLING DIAGNOSTIC SYSTEM CHECK? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF-DIAGNOSTIC. NOTE: Listen for an audible click when the cooling fan 1 relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. Install a scan tool. Turn ignition on, with engine off. With a scan tool, command the FANS LOW SPEED ON and OFF. Does the cooling fan 1 relay turn ON and OFF with each command? If so, go to «DIAGNOSTIC AIDS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-aids) . If not, go to next step. NOTE: Tests for voltage at the coil side of the cooling fan 1 relay. The cooling fan 1 fuse supplies battery positive voltage to the coil side of the cooling fan 1 relay.
3. Turn OFF the ignition. Disconnect the cooling fan 1 relay. Turn ignition on, with engine off. Probe the battery positive voltage circuit of the cooling fan 1 relay with a test light that is connected to a good ground. Does the test light illuminate? If so, go to next step. If not, go to step 8 . NOTE: Verifies that the PCM is providing ground to the cooling fan 1 relay.
4. Connect a test light between the low-speed cooling fan relay control circuit of the cooling fan 1 relay and the battery positive voltage circuit of the cooling fan 1 relay. With a scan tool, command the FANS LOW SPEED ON and OFF. Does the test light turn ON and OFF with each command? If so, go to step 10 . If not, go to next step. NOTE: Tests if ground is constantly being applied to the cooling fan 1 relay.
5. Does the test light remain illuminated with each command? If so, go to step 7 . If not, go to next step.
6. Test the low-speed cooling fan relay control circuit of the cooling fan 1 relay for a short to voltage or an open. Did you find and correct the condition? If so, go to step 14 . If not, go to step 9 .
7. Test the low-speed cooling fan relay control circuit of the cooling fan 1 relay for a short to ground. Did you find and correct the condition? If so, go to step 14 . If not, go to step 9 .
8. Test the battery positive voltage circuit of the cooling fan 1 relay for a short to ground or an open. Did you complete the repair? If so, go to step 14 . If not, go to step 11 .
9. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If so, go to step 14 . If not, go to step 13 .
10. Inspect for poor connections at the cooling fan 1 relay. Did you find and correct the condition? If so, go to step 14 . If not, go to step 12
11. Repair the cooling fan motor supply voltage circuit for a short to ground. After repairs are complete, go to step 14 .
12. Replace the cooling fan 1 relay. After replacement is complete, go to step 14 .
13. Replace the PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. After replacement is complete, go to next step.
14. Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. See «CONDITIONS FOR RUNNING THE DTC»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__conditions-for-running-the-dtc) . Does the DTC reset? If so, go to step 2 . If not, then system is okay.

Battery positive voltage is supplied to the cooling fan S/P relay and the cooling fan 2 relay from the cooling fan 2 fuse. The Powertrain Control Module (PCM) controls the relays by grounding the high speed cooling fan relay control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component on, the voltage potential of the control circuit should be low, near zero volts. When the PCM is commanding the control circuit to a component off, the voltage potential of the circuit should be high, near battery voltage. If the fault detection circuit senses a voltage other than what is expected, the DTC will set. The PCM will monitor the control circuit for the following

1. A short to ground.
2. A short to voltage.
3. An open circuit.

When the PCM detects any of the above conditions, the DTC will set and the affected driver will be disabled.

1. The ignition is ON.
2. The system voltage is between 9 and 18 volts.

1. An improper voltage level has been detected on the high speed cooling fan relay control circuit.
2. The above condition is present for at least 30 seconds.

1. The PCM will illuminate the Malfunction Indicator Light (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
2. The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
3. A history DTC is stored.

1. The PCM will turn the MIL OFF after three consecutive trips that the diagnostic has been run and passed.
2. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. The DTC can be cleared by using the scan tool Clear DTC Information function.

If the condition is not present, see INTERMITTENTS in SYMPTOMS - ENGINE PERFORMANCE under TROUBLE SHOOTING. Review the Freeze/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF-DIAGNOSTIC. NOTE: Listen for an audible click when the cooling fan S/P and the cooling fan 2 relays operate. Command both the ON and OFF states. Repeat the commands as necessary.
2. Install a scan tool. Turn ignition on, with engine off. With a scan tool, command the Fans High Speed ON and OFF. Does the cooling fan S/P and the cooling fan 2 relays turn ON and OFF with each command? If so, go to «DIAGNOSTIC AIDS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans) . If not, go to next step. NOTE: Tests for voltage at the coil side of the cooling fan 2 relay. The cooling fan 2 fuse supplies battery positive voltage to the coil side of the cooling fan 2 relay.
3. Turn OFF the ignition. Disconnect the cooling fan 2 relay. Turn ignition on, with engine off. Probe the battery positive voltage circuit of the cooling fan 2 relay with a test light that is connected to a good ground. Does the test light illuminate? If so, go to next step. If not, go to step 8 . NOTE: Verifies that the PCM is providing ground to the cooling fan 2 relay.
4. Connect a test light between the high-speed cooling fan relay control circuit of the cooling fan 2 relay and the battery positive voltage circuit of the cooling fan 2 relay. With a scan tool, command the FANS HIGH SPEED ON and OFF. Does the test light turn ON and OFF with each command? If so, go to step 9 . If not, go to next step. NOTE: Tests if ground is constantly being applied to the cooling fan 2 relay.
5. Does the test light remain illuminated with each command? If so, go to step 7 . If not, go to next step.
6. Test the high-speed cooling fan relay control circuit of the cooling fan S/P relay and the cooling fan 2 relay for a short to voltage or an open. Did you find and correct the condition? If so, go to step 12 . If not, go to step 9 .
7. Test the high-speed cooling fan relay control circuit of the cooling fan S/P relay and the cooling fan 2 relay for a short to ground. Did you find and correct the condition? If so, go to step 12 . If not, go to step 9 .
8. Test the battery positive voltage circuit of the cooling fan S/P relay and the cooling fan 2 relay for an open or a short to ground. Did you find and correct the condition? If so, go to step 12 . If not, go to step 10 .
9. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If so, go to step 12 . If not, go to step 11 .
10. Repair the cooling fan motor supply voltage circuit for a short to ground. After repair is complete, go to step 12 .
11. Replace the PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article under ENGINE PERFORMANCE. After repair is complete, go to next step.
12. Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. See «CONDITIONS FOR RUNNING THE DTC»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans) . Does the DTC reset? If so, go to step 2 . If not, then system is okay.

COOLING FAN ALWAYS ON

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF - DIAGNOSTIC.
2. Turn ignition on, with engine off. Are one or both cooling fans ON? If so, go to next step. If not, see «INTERMITTENTS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__intermittents) in SYMPTOMS - ENGINE COOLING under TROUBLE SHOOTING.
3. Are both cooling fans running continuously? If so, go to step 5 . If not, go to next step.
4. Remove the cooling fan S/P relay. Did the left cooling fan turn OFF? If so, go to step 6 . If not, go to step 7
5. Repair the short to voltage in the right cooling fan motor supply voltage circuit. After repair is complete, go to step 8 .
6. Repair the short to voltage in the cooling fan low reference circuit. After repair is complete, go to step 8 .
7. Repair the short to voltage in the left cooling fan motor supply voltage circuit. After repair is complete, go to next step.
8. Operate the system in order to verify the repair. Did you correct the condition? If so, system is okay. If not, go to step 2 .

COOLING FAN INOPERATIVE

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF-DIAGNOSTIC.
2. Install a scan tool. Turn ignition on, with engine off. With a scan tool, command the FANS LOW SPEED ON and OFF. Do the low speed engine cooling fans turn ON and OFF with each command? If so, go to next step. If not, go to step 4 . NOTE: Before the PCM changes the speed of the cooling fans, a 3-second delay will occur.
3. With a scan tool, command the FANS HIGH SPEED ON and OFF. Do the high speed engine cooling fans turn ON and OFF with each command? If so, see «INTERMITTENTS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__intermittents) in SYMPTOMS - ENGINE COOLING under TROUBLE SHOOTING. If not, go to step 11 . NOTE: Following this step, DO NOT remove the 20-amp fused jumper wire that is connected during this step. While performing the following steps, use a second 20-amp fused jumper wire.
4. Disconnect the cooling fan 1 relay. Connect the first 20-amp fused jumper between the battery positive voltage circuit of the cooling fan 1 relay and the cooling fan motor supply voltage circuit of the cooling fan 1 relay. Do both cooling fans operate in low speed? If so, go to step 13 . If not, go to next step.
5. Disconnect the cooling fan S/P relay. Connect the second 20-amp fused jumper between the right cooling fan ground circuit of the cooling fan S/P relay and the left cooling fan motor supply voltage circuit of the cooling fan S/P relay. Do both cooling fans operate in low speed? If so, go to step 14 . If not, go to next step.
6. Connect a 20-amp fused jumper between the battery positive voltage circuit of the cooling fan S/P relay and the cooling fan motor supply voltage circuit of the cooling fan S/P relay. Does the left cooling fan operate in high speed? If so, go to step 9 . If not, go to next step.
7. Install the cooling fan S/P relay. Disconnect the left cooling fan electrical connector. Connect the second 20-amp fused jumper wire from the cooling fan motor supply voltage circuit of the left cooling fan electrical connector to the ground circuit of the left cooling fan electrical connector. Does the right cooling fan operate in high speed? If so, go to step 16 . If not, go to next step.
8. Connect a 20-amp fused jumper wire from the cooling fan motor supply voltage circuit of the left cooling fan electrical connector to a good ground. Does the right cooling fan operate in high speed? If so, go to step 20 . If not, go to step 21 .
9. Install the cooling fan S/P relay. Disconnect the right cooling fan electrical connector. Connect the second 20-amp fused jumper wire from the cooling fan motor supply voltage circuit of the right cooling fan electrical connector to the cooling fan low reference circuit of the right cooling fan electrical connector. Does the left cooling fan operate in high speed? If so, go to step 17 . If not, go to next step.
10. Connect the second 20-amp fused jumper wire from battery positive voltage to the cooling fan low reference circuit of the of the right cooling fan electrical connector. Does the left cooling fan operate in high speed? If so, go to step 18 . If not, go to step 22 .
11. Is the left cooling fan operating properly in high speed? If so, go to next step. If not, go to step 15 .
12. Disconnect the cooling fan S/P relay. Connect the second 20-amp fused jumper between the cooling fan low reference circuit of the cooling fan S/P relay and the ground circuit of the cooling fan S/P relay. Does the right cooling fan operate properly in high speed? If so, go to step 14 . If not, go to step 19 .
13. Inspect for poor connections at the cooling fan 1 relay. Did you find and correct the condition? If so, go to step 28 . If not, go to step 23 .
14. Inspect for poor connections at the cooling fan S/P relay. Did you find and correct the condition? If so, go to step 28 . If not, go to step 24 .
15. Inspect for poor connections at the cooling fan 2 relay. Did you find and correct the condition? If so, go to step 28 . If not, go to step 25 .
16. Inspect for poor connections at the harness connector of the left cooling fan. Did you find and correct the condition? If so, go to step 28 . If not, go to step 26 .
17. Inspect for poor connections at the harness connector of the right cooling fan. Did you find and correct the condition? If so, go to step 28 . If not, go to step 27 .
18. Repair the right cooling fan motor supply voltage circuit. After repairs are complete, go to step 28 .
19. Repair the left cooling fan motor ground circuit. After repairs are complete, go to step 28 .
20. Repair the right cooling fan motor ground circuit. After repairs are complete, go to step 28 .
21. Repair the left cooling fan motor supply voltage circuit. Did you complete the repair? After repairs are complete, go to step 28 .
22. Repair the cooling fan low reference circuit. After repairs are complete, go to step 28 .
23. Replace the cooling fan 1 relay. After replacement is complete, go to step 28 .
24. Replace the cooling fan S/P relay. After replacement is complete, go to step 28 .
25. Replace the cooling fan 2 relay. After replacement is complete, go to step 28 .
26. Replace the left cooling fan. See «COOLING FAN MOTOR»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans) under REMOVAL & INSTALLATION. After replacement is complete, go to step 28 .
27. Replace the right cooling fan. See «COOLING FAN MOTOR»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans) under REMOVAL & INSTALLATION. After replacement is complete, go to next step.
28. Operate the system in order to verify the repair. Did you correct the condition? If so, then system is okay. If system is not okay, go to step 3 .

ENGINE COOLANT TEMPERATURE INDICATOR ALWAYS ON

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__diagnostic-system-check-engine-cooling) under SELF-DIAGNOSTIC.
2. Start the engine. Does the engine coolant temperature indicator illuminate? If so, go to next step. If not, see «INTERMITTENTS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__intermittents) in SYMPTOMS - ENGINE COOLING under TROUBLE SHOOTING.
3. Install a scan tool. Turn ON the ignition with the engine OFF. With the scan tool, observe the ENGINE COOLANT TEMPERATURE PARAMETER in the Powertrain Control Module (PCM) data list. Does the scan tool indicate that the coolant temperature is within the temperature range shown on the temperature gauge? If so, go to «ENGINE OVERHEATING»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__engine-overheating) . If not, go to next step.
4. Replace the IPC. See appropriate GAUGES & INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs are complete, go to next step.
5. Operate the system in order to verify the repair. Did you correct the condition? If so, then system is okay. If system is not okay, go to 2 .

ENGINE OVERHEATING

Check for possible causes of engine overheating. Inspect and fill the cooling system as necessary.

REMOVAL & INSTALLATION

Note. Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Note. If abnormal noise or vibration is felt from the engine compartment, inspect and clean any foreign material from the cooling fan blades.

Removal

1. Disconnect the battery negative cable. Remove the upper radiator support bar. Disconnect the wiring harness electrical connector from the motor and the fan bracket. (Scheme 1)
2. Remove the transaxle oil cooler pipe bracket bolt from the fan shroud. Remove the 2 fan mounting bolts. (Scheme 2) Lift the fan assembly off the lower holding tabs and remove from the vehicle.

Scheme 1

Scheme 2

Installation

1. Install the fan assembly and insert into the lower radiator holding tabs. Install the electric cooling fan mounting bolts. Tighten the bolts to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications).
2. Align the transaxle oil cooler pipes with the routing features on the fan shroud. (Scheme 3) Install the transaxle oil cooler pipe bracket bolt to the fan shroud. Tighten the bolt to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications). (Scheme 2)
3. Connect the wiring harness electrical connectors to the fan motors. Install the upper radiator support bar. Tighten support bolts to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications). Connect the battery negative cable. Tighten cable to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications).

Scheme 3

1. Remove the electric cooling fan. See «COOLING FAN»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans).
2. The fan blade retaining nut is left hand thread. Remove the fan blade retaining nut from the electric cooling fan motors. (Scheme 4)
3. Remove the fan blade from the motor shaft. Remove the cooling fan motor retaining screws. (Scheme 4) Remove the cooling fan motor from the shroud.

Scheme 4

1. Install the cooling fan motor to the shroud. (Scheme 4) Install the cooling fan motor retaining bolts. (Scheme 4) Tighten the bolts to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications).
2. Install the cooling fan blade to the motor shaft. (Scheme 4) The fan blade retaining nut is left hand thread. Install the cooling fan retaining nut to the motors. Tighten the nut to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/cooling-fan/#electric-cooling-fans__torque-specifications). Install the electric cooling fan.

Note. Required Tools: Relay Puller Pliers (J-43244).

Note. Always note the orientation of the relay. Ensure that the electrical center is secure, as not to put added stress on the wires or terminals.

1. Remove the electrical center cover.
2. Locate the relay. See «FUSES & CIRCUIT BREAKERS»(/buick/lesabre/viii-2000-2005/remont/fuses-circuit-breakers/#fuses-circuit-breakers) article in ELECTRICAL. NOTE: Use Relay Puller Pliers to pull the relay straight out from the electrical center terminals. The use of pliers or a flat bladed tool could damage the electrical center.
3. Using the Relay Puller Pliers position the tool on opposing corners of the relay. (Scheme 5) Remove the relay from the electrical center.

Scheme 5

Install the relay in the same position as removed. Install the electrical center cover.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Scheme 6

Scheme 7

Scheme 8

Scheme 9

BONNEVILLE

For wiring diagrams, see COOLING FAN in appropriate SYSTEM WIRING DIAGRAMS article under ELECTRICAL.

LESABRE

For wiring diagrams, see COOLING FAN in appropriate SYSTEM WIRING DIAGRAMS article under ELECTRICAL.

See also:
• COMPUTER RELEARN PROCEDURES
• FUSES & CIRCUIT BREAKERS
• WIRING DIAGRAMS
• DIAGNOSTIC SYSTEM CHECK - ENGINE COOLING
• DESCRIPTION & OPERATION
• ENGINE COOLANT TEMPERATURE INDICATOR ALWAYS ON
• COOLING FAN ALWAYS ON
• COOLING FAN INOPERATIVE
• ENGINE OVERHEATING
• SYMPTOMS - ENGINE COOLING
• DIAGNOSTIC TROUBLE CODE DEFINITIONS
• INTERMITTENTS
• DIAGNOSTIC AIDS
• CONDITIONS FOR RUNNING THE DTC
• TORQUE SPECIFICATIONS