I'm curious, yesterday when car was idle for approximately 10 minutes the car was heating up nearly to the red zone. I'm residing in AZ so the outside temp was approx. 107. My friend took at look at it tonight, he burped the radiator stating some air was in it. But when either the ac or heat was on full blast the radiator coolant fan did not turn on. The car was at idle for about 20 minutes during the entire check. I'm not sure if the fan turns on at extreme temps. Or if it is suppose to turn on when ac is on. When does it turn on? We are both confused by this and seeking advice.

 

I moved your thread to the proper section for help.

1. Is this a 4 or 6 cylinder?

2. With the A/C on, both A/C condenser fan and radiator fan should run. Is it only one fan running; if so, which fan motor is not running (driver (left) side or passenger (right) side)?

3. For a 2004 Accord 4 cylinder: if the coolant temperature is above 196 degrees at the radiator fan switch, both fans should also run.

For a 2004 Accord 6 cylinder:

• In normal operating temperature conditions, the PCM (car's computer) gets input from the ECT (Engine Coolant Temperature) sensor to turn on the A/C condenser fan as needed.

• In extremely high operating temperature conditions, the PCM (car's computer) gets input from the ECT (Engine Coolant Temperature) sensor and will turn on both the A/C condenser fan and radiator fan as needed.

 

It is a 4 cylinder. The fan that did not kick on is the fan located on the passenger side. We had the ac turned on all the way as well. The coolant was running, just that fan did not turn on at all.

 

How can we check the coolant temp; whether it is above 196? Will we have to use a thermometer in the coolant opening?

 

Never let your car heat up to the red zone. This can cause engine damage. Always turn on the heat full blast with outside air to help cool the engine. You may be miserable in the car, but this helps cool the engine.

Both fans turn on when the coolant temperature reaches a certain point. Both fans also turn on when you turn on the a/c with the engine running.

A quick fan test is to start the engine when it is cold and turn on the a/c. If you have no fans or one fan, you need to determine why the fan is not working. I'd unplug the fan that is not working and use a volt meter to verify that fan is getting 12V.

The term a/c and radiator fan don't mean that one fan cools the radiator and the other cools the a/c condenser. When describing the motors, use driver's side or passenger side fan motor to help us provide more detailed testing.

Good Luck.

 

Redbull posted before me.

I wouldn't worry about measuring the temperature of the coolant. If the needle in the dash is above the 1/2 way mark, then both fans should have turned on.

Does the overheat happen only at idle? Will the temperature lower when the car is moving?

 

1. First check under-hood Fuse No. 9 (20A). If it is blown, replace with same amperage fuse, do not use a higher amperage fuse.

2. If Fuse No. 9 is okay, it may be problem with the A/C condenser motor, relay, or wiring. You can disconnect the A/C fan motor connector and apply direct battery power (+) and ground (-) to the motor side. Apply battery power to the A/C condenser fan motor red wire, and ground to the fan motor black wire on the gray connector. If the fan does not run strongly by applying direct battery power and ground, the motor is bad and needs replacement.

3. Alternately, another test is to disconnect the gray electrical connector to the radiator fan switch (located at the bottom of the radiator) and jump the gray harness connector's terminals with a jumper wire; then turn the ignition switch ON, both fans should run. -- However, this test may not be necessary, as it sounds like a problem with the A/C condenser fan motor and not this fan switch.

 

The car over heated at idle only. When the car drives it cools down.

 

Thanks Redbull! Will take a check in the AM and post results!

 

Post your results. It does sound like an issue with the A/C condenser fan circuit. Remember, check that fuse first.