The radiator fan switch, also known as the coolant temperature switch, plays a key role in keeping your 1992–2001 2.2L Toyota Camry's engine cool.
This little component is mounted on the bottom tank of the radiator and works alongside the radiator fan relays to control the cooling fans.
In this tutorial, I'll explain what the coolant temp switch does, how it works, and how to test it without removing it from the radiator.
Contents of this tutorial:
- Radiator Fan Switch Basics.
- Symptoms Of A Bad Radiator Fan Switch.
- Where To Buy The Radiator Fan Switch.
- TEST 1: Checking Radiator And Condenser Fan Fuses.
- TEST 2: Activating The Radiator And Condenser Fan Motors.
- TEST 3: Checking Fan Operation With The Engine Running (With A Scan Tool).
- TEST 4: Checking Fan Operation With The Engine Running (With A Infrared Thermometer).
- More 2.2L Toyota Camry Tutorials.
APPLIES TO: This tutorial applies to the following vehicles:
- 2.2L Toyota Camry: 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001.
Wiring Diagrams: You can find the radiator fan motor wiring diagrams here:
- Cooling Fan Circuit Wiring Diagram (1992-1996 2.2L Toyota Camry).
- Cooling Fan Circuit Wiring Diagram (1997-2001 2.2L Toyota Camry).
Engine Overheating Diagnostics: The following tutorials will help you troubleshoot an engine overheating problem:
- Common Causes Of Engine Overheating (1992-2001 2.2L Toyota Camry).
- How To Test The Radiator And Condenser Fan Motor (1992-2001 2.2L Toyota Camry).
- How To Test The Thermostat (1992-2001 2.2L Toyota Camry).
- How To Test For A Blown Head Gasket (1990-2001 2.2L Toyota Camry).
Radiator Fan Switch Basics
The radiator fan switch plays a key role in regulating the operation of your Camry's radiator and condenser fans. Here's what you need to know:
- Location: Found on the bottom tank of the radiator.
- NOTE: You can identify the coolant temperature switch by its connector, which has two wires: one blue with white stripe (BLU/WHT) and one white with black stripe (BLK).
- Function Below 181°F: The switch is normally closed, meaning there's continuity between its two terminals. This keeps the radiator fans off, allowing the engine to warm up to its optimal operating temperature.
- Function Above 199°F: The switch opens, breaking continuity between the terminals. This activates both the radiator fan and condenser fan, pulling air across the radiator to cool the engine.
There are several methods to test the coolant temp switch, but I'll show you the simple and effective way that I've been doing it for years and it doesn't require removing it.
Symptoms Of A Bad Radiator Fan Switch
Over time, the radiator fan switch will fail, preventing it from properly detecting the coolant temperature or activating the radiator fan relay.
When the radiator fan switch stops working, it can lead to engine overheating and other related issues because the radiator fan won't turn on as needed.
These are some common symptoms of a bad radiator fan switch in the 1992-2001 2.2L Toyota Camry:
- Engine overheating: The engine temperature rises, especially when idling or in stop-and-go traffic, because the radiator fan isn't activated to cool the engine.
- Radiator fans not turning on: The radiator fan fails to engage even when the coolant temperature exceeds 190°F.
- Intermittent fan operation: The radiator fan works sporadically or fails to run consistently due to an unreliable signal from the switch.
- The radiator fan relay doesn't activate: The relay doesn't receive the necessary Ground signal from the radiator fan switch to activate.
- Cooling fans running constantly: If the switch fails in the "open" position, the fans may stay on even when the engine coolant is below 199°F. This can result in poor fuel economy and excessive wear on the fan motor.
Where To Buy The Radiator Fan Switch
The coolant temperature switch (radiator fan switch) on the 1992-2001 2.2L Toyota Camry isn't an expensive part. The following links will help you comparison shop for it (and it's connector) and save a few bucks:
TEST 1: Checking Radiator And Condenser Fan Fuses
IMPORTANT: Before you begin your radiator fan switch diagnostic, it's important that you first confirm that the amperage draw of the radiator and condenser fan motors are under 30 Amps! This is a super easy test that's done with a multimeter and you can find it explained here:
To get our coolant temp switch started, we're gonna start by checking CDS Fuse (30A) and the RDI Fuse (30A) are OK.
Both of these fuses are located in the engine compartment fuse/relay box.
Let's get started:
- 1
Locate the CDS Fuse (30A) in the under-hood fuse box of your Toyota Camry.
The CDS Fuse (30A) supplies power to the A/C condenser fan motor.
The condenser fan is the one located on the right (passenger) side of the radiator. - 2
Remove the fuse and check its condition.
- 3
Replace the fuse if blown with a fuse of the same rating (30A).
- 4
Locate the RDI Fuse (30A) in the under-hood fuse box of your Toyota Camry.
The RDI Fuse (30A) supplies power to the radiator fan motor.
The radiator fan is the one located on the left (driver) side of the radiator. - 5
Remove the fuse and check its condition.
- 6
Replace the fuse if blown with a fuse of the same rating (30A).
Let's interpret your test result:
CASE 1: Both fuses are OK. This is the correct and expected test result.
Your next step is to go to: TEST 2: Activating The Radiator And Condenser Fan Motors.
CASE 3: The CDS fuse was blown. This usually tells you that the A/C condenser fan motor has a high amperage draw. This high amperage draw will blow the fuse every time the condenser fan motor activates.
Replace the fuse with a fuse of the same rating. I also recommend checking the amperage draw of the fan motor. The following tutorial explains how:
If the amperage draw is within the correct range, your next step is to go to: TEST 2: Activating The Radiator And Condenser Fan Motors.
CASE 3: The RDI fuse was blown. This usually tells you that the radiator fan motor has a high amperage draw. This high amperage draw will blow the fuse every time the radiator fan motor activates.
Replace the fuse with a fuse of the same rating. I also recommend checking the amperage draw of the fan motor. The following tutorial explains how:
If the amperage draw is within the correct range, your next step is to go to: TEST 2: Activating The Radiator And Condenser Fan Motors.
TEST 2: Activating The Radiator And Condenser Fan Motors
So far, you've confirmed:
- Neither fan motor is drawing 30 amps or more.
- The CDS fuse and RDI fuse are intact (as checked in TEST 1).
Next, we'll test the operation of the fan relays and both fan motors while they're connected and installed in their usual positions in the engine compartment.
We'll easily accomplish this by disconnecting the radiator fan switch from its electrical connector and then turning the key to the ON position.
These are the test steps:
- 1
Locate the radiator fan switch.
LOCATION: The radiator fan switch is located on the bottom radiator tank, facing the engine. - 2
Disconnect the radiator fan switch from its electrical connector.
- 3
Turn the key to the ON position but don't crank or start the engine.
- 4
Both fans should turn ON.
Let's take a look at what your test results mean:
CASE 1: Both fan motors turned ON. This is the correct and expected test result.
With this result, you've confirmed that the entire electrical circuit for the fan motors is working properly. Specifically, this means:
- The fan relays are functioning correctly.
- There are no wiring issues between the radiator fan switch and the fan relays or between the fan relays and the fan motors.
Your next step:
If you have a generic scan tool with "live data" capability and your Camry is OBD II equipped (1996-2001), go to: TEST 3: Checking Fan Operation With The Engine Running (With A Scan Tool).
If you DON'T have a generic scan tool or your Camry IS NOT OBD II equipped (1992-1995), go to: TEST 4: Checking Fan Operation With The Engine Running (With A Infrared Thermometer).
CASE 2: Both fan motors DID NOT turn ON. This test result usually points to a bad radiator fan relay (and there's 3 of them).
Testing the radiator fan relays is your next step. Although it's beyond the scope of this tutorial, you'll need to verify whether one or more of the relays are faulty.
CASE 3: The radiator fan motor DID NOT turn ON. This result indicates a problem isolated to the radiator fan motor circuit (wiring), only if you have:
- Tested the amperage draw of the radiator fan motor.
- Checked its operation by applying 12 Volts and Ground from the battery.
Although it's beyond the scope of this tutorial, your next step is to:
- Check for an open-circuit problem in the blue (BLU) wire between the radiator fan motor connector and Radiator Fan Relay 1.
- Check for an open-circuit problem in the white with black stripe (WHT/BLK) wire between the radiator fan motor connector and chassis Ground.
CASE 4: The condenser fan motor DID NOT turn ON. This result indicates a problem isolated to the condenser fan motor circuit (wiring), only if you have:
- Tested the amperage draw of the condenser fan motor.
- Checked its operation by applying 12 Volts and Ground from the battery.
Although it's beyond the scope of this tutorial, your next step is to:
- Check for an open-circuit problem in the black with red stripe (BLK/RED) wire between the condenser fan motor connector and CDS Fuse (30A).
- Check for an open-circuit problem in the red (RED) wire between the condenser fan motor connector and Radiator Fan Relay 2.