TEST 3: Checking Fan Operation With The Engine Running (With A Scan Tool)
In this test section, we're gonna check if the fan motors activate when the engine coolant temp reaches a certain range.
This test will help us verify if Radiator Fan Switch 1 is correctly activating the fan motors at its activation temperature.
To monitor the engine's coolant temperature accurately, we need to use a scan tool with "live data" capability. This scan tool will allow us to monitor the engine coolant temp in real time.
If the radiator fan switch is OK, both fans should activate when the engine coolant temp reaches a temperature between 220°F and 225°F.
If the radiator fan switch is working properly, both fans should activate once the coolant temperature hits 220°F to 225°F.
IMPORTANT: Do not continue with this test if, during TEST 2, the fan motors did not turn on when the radiator fan switch was unplugged and the key was turned to the ON position.
CAUTION: Accessing the radiator fan switch on a 1997-2001 3.0L Camry, you'll need to lift the vehicle. Always use jack stands to ensure the vehicle is securely raised —never rely on the jack alone!
NOTE: The temperature shown on your scan tool will likely be higher than the radiator fan switch's actual activation point. This happens because the scan tool reads data from the Engine Coolant Temp (ECT) sensor, which is located in a hotter area of the engine. While Radiator Fan Switch 1 is designed to activate at 208°F and above, the scan tool might display a higher reading. This difference is normal and nothing to worry about.
These are the test steps:
- 1
Reconnect the radiator fan switch to its connector.
- 2
Check the coolant level in the radiator.
If it's low, top it off with coolant or water before proceeding to the next steps. - 3
Connect your generic scan tool to your Toyota Camry's diagnostic link connector.
- 4
Access the "live data" feature on your scan tool and locate the "ECT" (Engine Coolant Temperature) or "COOLANT" PID (see photo above).
- 5
Start the engine and let it idle.
- 6
Monitor the ECT temperature on your scan tool as the engine idles.
- 7
The radiator fan motor should turn ON when the ECT temperature reaches between 220°F to 225°F.
NOTE: It's normal for the fan motor to activate closer to 220°F. - 8
If the radiator fan motor hasn't turned on by 225°F, turn the engine OFF immediately to avoid overheating.
Place a house fan over the engine to cool it down.
Alternatively, you can disconnect the radiator fan switch and turn the key to the ON position to force the fans to activate and cool the engine down.
Let's take a look at your test results:
CASE 1: The fan motors turned ON at the indicated temperature range. This the correct and expected test result.
This test result tells you that the radiator fan switch is good and not the cause of the engine's overheating problem.
If your Toyota Camry is overheating, I suggest you test the engine coolant thermostat and doing a blown head gasket test.
CASE 2: The fan motors DID NOT turn ON. This confirms that the radiator fan switch is not functioning and needs to be replaced, if you have:
- Confirmed that the combined amperage draw of both fans is under 30 Amps.
- Confirmed that the operation of both fans by directly applying 12 Volts and Ground to them.
- Confirmed that the radiator and condenser fan fuses are OK (TEST 1).
- Confirmed that the operation of both fans by disconnecting the radiator fan switch and turning the key to the ON position (TEST 2).
- Confirmed in this test section that the fans are not activated at the indicated temperature.
TEST 4: Checking Fan Operation With The Engine Running (With A Infrared Thermometer)
In this test section, we're gonna check if the fan motors activate when Radiator Fan Switch 1 reaches its activation temperature.
The easiest and most accurate way to do this is with a scan tool with "live data" capability. We can also use an infrared laser thermometer to monitor the switch's surface temperature without physical contact.
If the radiator fan switch is functioning correctly, both fans should activate when its surface temperature reaches 208°F.
IMPORTANT: Do not proceed with this test if, during TEST 2, the fan motors failed to activate when the radiator fan switch was disconnected and the key was turned to the ON position.
CAUTION: Accessing the radiator fan switch on a 1997-2001 3.0L Camry, you'll need to lift the vehicle. Always use jack stands to ensure the vehicle is securely raised —never rely on the jack alone!
Let's get started:
- 1
Reconnect radiator fan switch 1 to its connector.
- 2
Check the coolant level in the radiator.
Top it off if needed before proceeding. - 3
Start the engine and let it idle and warm up to operating temperature.
- 4
Point the laser directly at the metal base of the radiator fan switch.
- 5
Monitor the temperature of the radiator fan switch.
Use the infrared thermometer to track its temperature. - 6
Check fan activation.
When the radiator fan switch's temperature reaches 208°F or above, both fan motors should turn ON to cool the engine coolant. - 7
If the fans don't activate turn off the engine.
If the temperature exceeds 215°F, turn the engine OFF immediately to avoid overheating. Place a box fan on the engine to cool the engine.
Alternatively, you can disconnect the radiator fan switch and turn the key to the ON position to force the fans to activate and cool the engine down.
Let's interpret your test result:
CASE 1: The fan motors turned ON at the indicated temperature range. This the correct and expected test result.
This test result tells you that the radiator fan switch is good and not the cause of the engine's overheating problem.
If your Toyota Camry is overheating, I suggest you test the engine coolant thermostat and doing a blown head gasket test.
CASE 2: The fan motors DID NOT turn ON. This result confirms that the radiator fan switch is faulty and needs to be replaced, provided you have:
- Verified that the combined amperage draw of both fans is under 30 Amps.
- Confirmed both fans operate correctly by directly applying 12 Volts and Ground to them.
- Checked that the radiator and condenser fan fuses are not blown (TEST 1).
- Confirmed fan operation by disconnecting Radiator Fan Switch 1 and turning the key to the ON position (TEST 2).
- Verified in this test that the fans did not activate at the specified temperature range.
More 3.0L Toyota Camry Tutorials
You can find a complete list of 3.0L Toyota Camry tutorials and wiring diagrams in this index:
Here's a sample of the tutorials you'll find there:
- How To Test Engine Compression (1992-2006 3.0L V6 Toyota Camry).
- How To Test For A Blown Head Gasket (1992-2006 3.0L V6 Toyota Camry).
- How To Test The TPS (1997-2001 3.0L V6 Toyota Camry).
- How To Test The MAF Sensor (1997-2001 3.0L V6 Toyota Camry).
If this info saved the day, buy me a beer!
