There is another thread here where the op had the exact problem I'm having:

https://www.hondaaccordforum.com/for...driving-36884/

I did as suggested and changed out both temperature switches. Also tried changing the temperature sensor to no avail. Both fans come on when a/c is on so I know the fans, relays are good.

I'm out of ideas. Anyone?

Thanks!

 

Just to ensure the circuit leading from the fan switch connector is okay, disconnect the green connector at the engine coolant temperature switch A (located on the thermostat housing - lower radiator hose) and use a small paper clip or wire and jumper the green connector plug. Turn the ignition to ON, does both fans run?

 

Thanks. yea, jumper turns on both fans. I assume the coolant temp switches (a&b) are the same. Do you know if thats the case? The part store only had one.

 

No, switch A and B are not the same. Switch A is suppose to be closed above 199 degrees F, whereas Switch B is suppose to be closed above 223 degrees F.

 

Hmmm....makes me wonder. The one I got said for the outlet which would be switch b. Maybe I need to get a factory part.

 

Is there another parts store around that may have Fan Switch A?

After you find and replace Switch A with the right part, do the following:

With the car sufficient cooled, check coolant level in both the radiator and reservoir.

Turn on the car and get the car to operating temperature.

Feel the lower radiator hose; does it get hot (almost as hot as the upper radiator hose)? If not, the thermostat may not have fully opened. The thermostat should be fully open at 194 degrees F. If it does not fully open at 194 F, it may be a bad thermostat. Rev the car a little to try to help get the coolant temp. up a little to see if that will open the thermostat.

Above 199 degrees F, the fan switch A (a normally open switch) should close and turn on the cooling fans.

Generally, with a properly working cooling system, the thermostat should be fully open before the cooling fans turn on.

 

Another possibility besides failed thermoswitch A. Thermostat is not allowing car to warm enough to close thermoswitch A. Does temperature gauge increase to just below horizontal position? If substantially lower, thermostat may be wrong thermstat or stuck open. '

good luck

 

Thanks for the responses.

Thinking out loud here. If switch B opens at 223 degrees, even if I put switch B where switch A goes, it should still kick the fan on before the motor gets really hot right?

The reason I ask is because with the new B switch in the A spot, the fan didn't come on even when the temperature gauge was at 3/4 which surely has to be over 223 degrees.

Does that make sense? I really don't want to spend another $40 if its highly unlikely to be the issue.

Checking the thermostat next.

 

Fans provide cooling when vehicle speed is slow and AC load is present. As long a forward speed is ~20mph or so, engine should not overheat If you are overheating while moving at speed, then thermostat is most likely problem, assuming you have good coolant level.

Thermoswitch B turns fans on w/ engine off to provent excess heating after shutdown.

You can test thermoswitch A directly in a pot of boiling water. Switch should close. If not, it's bad.

good luck

 

If the t-stat is bad and you replace it, be sure to bleed the air out of the system. Honda's do not like air in the coolant system. There should be a bleeder on the t-stat housing where the lower hose connects to the engine....use the proper procedure to bleed the system.

Air in they system will not allow the fan switches to read the temp properly...thus not turning on the fans when they should.