How To Test The Radiator Fan Motor (1995-2000 1.6L Honda Civic)

In this tutorial, I'll walk you through the step-by-step process for testing the radiator fan motor.

With your test results, you'll quickly figure out if the radiator fan motor is working properly or needs to be replaced.

APPLIES TO: This tutorial applies to the following vehicles:

• 1.6L Honda Civic CX: 1995, 1996, 1997, 1998, 1999, 2000.
• 1.6L Honda Civic DX: 1995, 1996, 1997, 1998, 1999, 2000.
• 1.6L Honda Civic EX: 1995, 1996, 1997, 1998, 1999, 2000.
• 1.6L Honda Civic LX: 1995, 1996, 1997, 1998, 1999, 2000.

WIRING DIAGRAM: You can find the radiator fan motor wiring diagram here:

• Radiator And Condenser Fan Motor Circuit Wiring Diagram (1995 1.6L Honda Civic).
• Radiator And Condenser Fan Motor Circuit Wiring Diagram (1996-1998 1.6L Honda Civic).
• Radiator And Condenser Fan Motor Circuit Wiring Diagram (1999-2000 1.6L Honda Civic).

Symptoms Of A Bad Radiator Fan Motor

When the engine reaches a certain coolant temperature, the PCM in your Honda Civic turns on the radiator fan to keep the engine cool.

Over time, the bearings in the radiator fan motor can wear out, causing the fan motor's shaft to experience more friction as it spins.

As this friction increases, the fan motor starts drawing more current to operate.

Eventually, this extra current can blow the radiator fan motor fuse or burn out the fan motor relay. When that happens, the radiator or condenser fan motor will stop working as it should.

These are some common symptoms of a bad radiator fan motor in a 1995–2000 1.6L Honda Civic:

• Engine Overheating: The engine temperature rises, especially when idling or in stop-and-go traffic, because one or both fans aren't effectively cooling the engine.
• Blown Fuse: The radiator fan motor fuse may blow repeatedly because the fan motor is drawing too much current.
• Burnt-Out Relay: A failing fan motor can burn out the radiator fan relay, preventing the fan from turning on.
• Strange Noises: Grinding or squealing sounds from the fan motor may signal worn-out bearings.
• Fan Not Turning On: The radiator fan doesn't engage when the engine gets hot.

Where To Buy The Radiator Fan Motor

The radiator fan motor on the 1997-2001 1.6L Honda Civic isn't an expensive part. The following links will help you comparison shop and save a few bucks:

TEST 1: Testing The Amperage Draw Of The Radiator Fan Motor

The first step is to find out if the fan motor is drawing too much current (a clear sign it's bad) by performing an amperage draw test.

To do this, you'll measure the fan motor's resistance with a multimeter set to Ohms mode and use Ohm's Law to calculate its amperage draw (Ohm's Law: Amps = Volts ÷ Ohms).

IMPORTANT: Make sure the fan motor blades don't move while you're measuring resistance. Any movement will throw off the reading and make the results inaccurate.

Let's dive in:

1. 1

   Disconnect the radiator fan motor from its electrical connector.

2. 2

   Place your multimeter in Ohms mode.

3. 3

   Measure the resistance of the fan motor across pins 1 and 2 with your multimeter (see photo above).
   
   NOTE: The test is done on the connector coming out of the fan motor. This connector has male spade terminals.

4. 4

   Divide your resistance value by 12.5. The result of this calculation is the amount of amperage the fan motor is using.
   
   To be a little more specific: Let's say that the resistance reading was 0.4 Ohms. This is what the math would look like: 12.5 ÷ 0.4 = 31.25 and this would translate to 31.25 Amps.

5. 5

   Amperage Draw Specification:
   
   Radiator fan motor: No greater than 20 Amps.
   
   Condenser fan motor: No greater than 20 Amps.

Let's take a look at your test results:

CASE 1: The amperage draw of the fan motor is within specification. This the correct and expected test result.

The next step is to manually apply battery power and Ground, from your Honda Civic's battery, to the fan motor itself. For this test go to: TEST 2: Applying Power And Ground To The Radiator Fan Motor.

CASE 2: The amperage draw is higher than specified for your 1997 or 1998-1999 Honda Civic's. This test result tells you that your Honda Civic's radiator fan motor is defective and needs to be replaced.

TEST 2: Applying Power And Ground To The Radiator Fan Motor

Now that you've confirmed the fan motor is drawing less than the specified amperage, it's time to move on to the next test. In this step, you'll apply battery power and ground directly to the radiator fan motor on your 1.6L Honda Civic.

To do this, you'll need a set of jumper wires to connect battery power and ground to the fan motor.

IMPORTANT: Only perform this test if the fan motor's amperage draw is less than 20 Amps. If it's 20 Amps or higher, the fan motor is bad—even if it runs when battery power and ground are applied.

These are the test steps:

1. 1

   Disconnect the fan motor from its electrical connector.
   
   The connector has 2 wires. The blue (BLU) wire supplies power and the black (BLK) wire supplies Ground.

2. 2

   Apply battery power to the fan motor terminal identified with the number 2 in the illustration above.
   
   You'll be applying power to the male spade terminal (of the radiator fan motor itself) that connects to the BLU wire of the electrical connector.

3. 3

   Apply chassis Ground to the radiator fan motor terminal identified with the number 1 in the illustration above.
   
   You'll be applying Ground to the male spade terminal (of the fan motor itself) that connects to the BLK wire of the electrical connector.

4. 4

   The radiator fan motor should run.

Let's take a look at your test results:

CASE 1: The radiator fan motor ran. This is the correct test result. You can conclude that your Honda Civic's radiator fan motor is not defective.

CASE 2: The radiator fan motor DID NOT run. This test result tells you that the radiator fan motor is defective and needs to be replaced.

More 1.6L Civic Tutorials

You can find a complete list of 1.6L Honda Civic tutorials in this index:

• 1.6L Honda Civic Index Of Articles.

Here's a small sample of the 1.6L Honda Civic tutorials you'll find in the index:

• Testing Shift Control Solenoid Valves A and B (1996-2000 1.6L Honda Civic).
• How To Test The Alternator (1996-2000 1.6L Honda Civic).
• How To Test: Lock-up Control Solenoid Valves (1996-2000 1.6L Honda Civic).
• How To Test Trouble Code P0135 (1995-2000 Honda 1.6L).
• How To Test The Igniter, Ignition Coil Accord, Civic, CRV, and Odyssey (at:easyautodiagnostics.com).