Cooling fan keeps running

The cooling fan on my partner’s 1995 Honda Odyssey occasionally keeps running after the ignition is turned off. When this happens it will continue running until the battery dies, so I have to pull the relay to get it to stop. My mechanic says everything checks out normally when he checks the car out. Any ideas on what to do?

Yes, replace the cooling fan relay. The problem is intermittent; so, what does that tell you about any checks on the relay? To me, it says that most of the time the relay will check good; thus, reinforcing the meaning of “intermittent”.

He has to go back and recheck his diagnostics.

The cooling fan control module is supplied with voltage all the time. When the coolant temp sensor on the side of the engine closes, it grounds the control module. The control module then sends voltage to the primary side of the relay to close the contacts so voltage is supplied to the cooling fan.

So it has to be the coolant temp sensor, the control module, or the relay.


For the time being when this happens smack the relay with a screwdriver handle. Then buy a new relay and have it rechecked as Tester stated.

A new relay tomorrow. I hope that takes care of it–taking a chance on needing to pop the hood and deal with the relay in the constantly raining Puget Sound weather is not attractive. Thanks for your advice.

Thanks for the advice. New relay tomorrow, and I hope that takes care of it. If not, I’ll go to tester’s advice.

Tester, thanks for the very complete and clear advice. Tomorrow a new relay. If that doesn’t take care of it, I’ll follow your path.