How to Test Radiator Fan Motor (Honda 2.2L, 2.3L)

In this tutorial, I'm gonna' show you how to test the radiator fan motor on your Honda Accord in a step-by-step manner.

Testing the radiator fan motor is not hard and it's something that you can do yourself.

So, if you're Honda has been overheating and you suspect the radiator fan motor has failed.. then this is the tutorial you need to find out, before you buy it, if the radiator fan motor is fried or not.

I'm also gonna' show you were you can buy it and save some bucks.

Here are the contents of this tutorial at a glance:

  1. Symptoms of a Bad Radiator Fan Motor.
  2. Honda Accord Radiator Fan Motor Basics.
  3. START HERE: Troubleshooting the Radiator Fan Motor.
  4. TEST 1: Applying Power and Ground to the Radiator Fan Motor.
  5. TEST 2: Bypassing the Radiator Fan Switch.
  6. Jumper Wire With Alligator Clips With Rubber Insulating Protectors.
  7. Where to Buy the Radiator Fan Motor and Save.
  8. More Honda Accord Test Tutorials.

Symptoms of a Bad Radiator Fan Motor

Since the radiator fan motor is one of the principal components of the engine's cooling system... when it fails, the most obvious symptom your Honda Accord is gonna' experience is overheating.

You may also see one or more of the following:

  1. Your temperature gauge will max out (as you're driving around).
  2. Your Honda will not re-start (once it has overheated).
  3. Coolant (or water) boiling in the radiator's overflow tank as the engine runs or when you turn off the engine.
  4. Coolant boiling in the radiator's overflow tank and the radiator fan motor does not activate.

NOTE: An overheating engine runs the risk of blowing its head gasket, so if your Honda is overheating, you should park it and get the problem diagnosed and repaired.

Honda Accord Radiator Fan Motor Basics

How to Test Radiator Fan Motor (Honda 2.2L, 2.3L)

There's a good chance your Honda has 2 fan motors. If this is the case, this also means that your Honda is A/C equipped.

The one on the passenger side of the engine compartment is the radiator fan motor and the one on the driver side is the condenser fan motor (see photo in the image viewer).

On vehicles with factory installed A/C, the radiator fan motor is both controlled by the PCM (Powertrain Control Module = fuel injection computer) and a radiator fan switch.

On vehicles with no A/C, the radiator fan motor is controlled only by a radiator fan switch.

Here are some more specifics:

  1. The fan motor is controlled by the following important components.
    1. Radiator fan motor relay.
    2. Radiator fan switch.
    3. Fuses (both in the under hood fuse box and in-dash fuse box).
  2. The radiator fan switch closes above 199°F (93°C).
    1. This means that the radiator fan switch turns on the radiator fan relay... which in turns activates the radiator fan motor.
  3. If your vehicle is A/C equipped.
    1. With the A/C off... only the radiator fan motor comes on when the temperature reaches about 225°F and then turns off when the temperature reaches somewhere below 200°F.
    2. With the A/C on... both fans are activated and run continuously until the A/C is turned off.
  4. If your vehicle IS NOT A/C equipped.
    1. The radiator fan is activated only when the radiator fan switch reaches a temperature above 199°F (93°C).
    2. Once the coolant temperature decreases below 199°F (93°C), the radiator fan motor turns off.

START HERE: Troubleshooting the Radiator Fan Motor

Since this is an in-depth tutorial, with several tests, on how to diagnose the radiator fan motor on your Honda Accord... I'm gonna' give you a brief summary of the tests I'm gonna' be showing you how to do.

Alright, we're gonna' start off by:

  1. Applying 12 Volts and ground to the radiator fan motor.
    1. This involves unplugging the radiator fan motor and directly applying power (12 volts) and ground to it.
    2. With this test, we're gonna' eliminate the radiator fan motor ‘right off the bat’ as being bad or not.
    3. TEST 1: Applying Power and Ground to the Radiator Fan Motor.
  2. Bypassing the radiator fan switch.
    1. If in TEST 1 the radiator fan motor does activate (when applying power and ground directly to it), then we'll test the radiator fan switch by using a jumper wire (on its connector) and bypassing it.
    2. TEST 2: Bypassing the Radiator Fan Motor Switch.

NOTE: You can modify the above tests to suit your particular diagnostic needs. If you don't have much troubleshooting experience, then I recommend starting from TEST 1.