Irregular radiator fan operation

[19dabeast85]

I washed my engine bay the other day and just got around to driving it today. Other than a bad idle that straightened itself out after driving for a bit, it seemed fine. (I'm always scared after a wash the engine area).

But my issue is that when I shut the car off after getting home, the radiator fan immediately came on. If I switch the car ON (or start), the fan turns off but comes right back on after I switch the car OFF.

So I came in a searched around and found that this is "normal" if temp are really hot outside, but my car has NEVER done this before through 2 summers (and it was only ~90 today anyway). I timed the fan, and it runs for exactly 15 minutes then shuts off, but i can go and switch ON->OFF and it will run for another 15.

So my question is: why would the car all of a sudden start doing this if it has never done it before even through 2 summers and hotter weather than today?

[NAiL05]

Check the fan timer.

[19dabeast85]

A new fan timer from Majestic Honda is $100.00. Is there any way to test it to make sure that IS the problem before I go replacing things? Am I correct in that it is located above the driver's feet under the dash?

[Otto]

Well the fan timer works, because its coming on after shutdown, and turns off after its 15 minute time elapses, and the fan shuts down with the key on. All these are correct. BUT...I find it takes a few moments to a minute before the fan comes on, and its only for a minute or two, never the full 15 minutes.
I need to check out the schematics, cause I forget how the rest of the curcuit works. ack

[F20A CB7]

when i turn my car off to it does the same thing stays on for aobut 15min

but my temp never goes up to over heat, the fan runs fine jus takes long to shut off the guy told me to check my thermo temp switch

[19dabeast85]

I just looked at some diagrams and figured out how to test:

The connector at the head on the upper radiator hose is a temperature switch for the radiator fan. When temps get high enough, contacts inside the switch touch creating a completed circuit and thus electricity to the fan (or fan timer).

When the engine is cold, these contacts should not be touching though and this is what we are dealing with here.

1. be sure engine is COLD.
2. pop the hood and disconnect the connector at the upper radiator hose/head.
3. switch car ON, then OFF (fan should NOT come on b/c impossible for circuit)
4. take paper clip and loop the 2 contacts on the harness (fan should come on)
5. pull paper clip out (fan turns off)
6. connect back to sensor/switch (fan will come on again)

this means that while cold, the switch is still internally touching and thus is bad and needs to be replaced.

IF, however, step 4 does NOT cause the fan to ingage, then you have a problem elsewhere.

I hope this helps you. It's time for a new switch for me. I must have fried it when I washed the engine, or maybe it was coincidence...?

[NAiL05]

MY old auto EX used to stay on 5-10 min max so dunno. Some people have said its supposed to be 15 min max so that beats me how long it really is supposed to stay on.

[Otto]

It is 15 minutes or till the temp. comes down, which ever comes first.

[oranger]

I washed my engine bay the other day and just got around to driving it today. Other than a bad idle that straightened itself out after driving for a bit, it seemed fine. (I'm always scared after a wash the engine area).

But my issue is that when I shut the car off after getting home, the radiator fan immediately came on. If I switch the car ON (or start), the fan turns off but comes right back on after I switch the car OFF.

So I came in a searched around and found that this is "normal" if temp are really hot outside, but my car has NEVER done this before through 2 summers (and it was only ~90 today anyway). I timed the fan, and it runs for exactly 15 minutes then shuts off, but i can go and switch ON->OFF and it will run for another 15.

So my question is: why would the car all of a sudden start doing this if it has never done it before even through 2 summers and hotter weather than today?

Dude, thats exactly how the fan is supposed to work. If it hasn't done that before it wasn't working correctly. That's all there is to it...

[19dabeast85]

Dude, thats exactly how the fan is supposed to work. If it hasn't done that before it wasn't working correctly. That's all there is to it...

Actually, it wasn't operating correctly because the engine temp was not enough to make the fan come on, new switch is on the way.

[sinistercb7]

My car did the same thing after i washed my motor on the top radiator hose the housing has a plug check it out mine hade some water in it dried it out and every thing went back to normal