TEST 3: Checking Fan Operation With The Engine Running (With A Scan Tool)
NOTE: This test only applies to the 1996-2001 OBD II equipped Toyota Camry.
In this section, we'll test the operation of the radiator and condenser fan motors with the engine running.
To perform this test, you'll need a scan tool with “live data” capability. This feature allows you to monitor the engine coolant temperature in real time.
Here's what to look for:
- When the coolant temperature reaches between 220°F and 225°F, both fans should activate to cool the coolant back down to below 190°F.
It's important to note that the radiator fan switch activates at 199°F+. However, the scan tool's temperature reading may show a slightly higher activation point because it uses data from the engine coolant temperature (ECT) sensor, which is located on the cylinder head.
This difference is normal. The ECT sensor typically reads a few degrees higher than the radiator fan switch because of its location in the cooling system. It's simply a result of the two sensors measuring coolant at different points -no need to worry about this discrepancy.
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.
These are the test steps:
- 1
Check the coolant level in the radiator.
If it's low, top it off with coolant or water before proceeding to the next steps. - 2
Connect your generic scan tool to your Toyota Camry's diagnostic link connector.
- 3
Access the "live data" feature on your scan tool and locate the "ECT" (Engine Coolant Temperature) or "COOLANT" PID (see photo above).
- 4
Start the engine and let it idle.
- 5
Monitor the ECT temperature on your scan tool as the engine idles.
- 6
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. - 7
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 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 section, we'll test the operation of the radiator and condenser fan motors using an infrared laser thermometer to monitor the radiator fan switch's temperature on the bottom tank of the radiator.
Here's what to look for: When the radiator fan switch's temperature reaches 199°F or above, both fan motors should activate to cool the engine coolant.
If both fans activate at 199°F or above, we can conclude that the switch is OK. If they don't, then the switch is bad and needs to be replaced.
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.
Let's get started:
- 1
Check the coolant level in the radiator.
Top it off if needed before proceeding. - 2
Locate the radiator fan switch.
The radiator fan switch is located on the bottom tank of the radiator. - 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 199°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 210°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 confirms that the radiator fan switch is not functioning and needs to be replaced, if you have:
- Confirmed that the 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.
More 2.2L Toyota Camry Tutorials
You can find a complete list of 2.2L 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 (1990-2001 2.2L Toyota Camry, Celica).
- How To Test The TPS With A Multimeter (1997-2001 2.2L Toyota Camry).
- How To Test For A Blown Head Gasket (1990-2001 2.2L Toyota Camry, Celica).
- How To Test The Throttle Position Sensor (1992-1996 2.2L Toyota Camry).
If this info saved the day, buy me a beer!
