It seems like neither of my fan switches work. When my car over heats, the fan switch located at the thermostat doesn't kick in, and when I turn off my car the second fan switch located at the water outlet should kick it on due to the car being overheated, but it doesn't. I've tried jumping the switch at the thermostat while the car is on, and that will kick in both radiator fans. I also jumped the switch at the water outlet when the car is off, and that will also kick in both radiator fans. Any ideas of whats wrong, or more things to look/test for? Oh and BTW those 2 fan switches are brand new and genuine honda parts. I replaced them because earlier the fan switch on the water outlet was permanently stuck on the ON position, and the fan switch on the thermostat wouldn't turn on.

 

I'm thinking there is another relay/sensor that is going out of whack. bit what troubles me is that if I jump the switch. that fans do turn on. Its highly improbably that I installed 2 bad switches which came brand new from honda.

 

Check the fan control module, little black box to the left of the ecu.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mgags7 &raquo;</TD></TR><TR><TD CLASS="quote">Check the fan control module, little black box to the left of the ecu.</TD></TR></TABLE>

+1 for that, I had the same problem and replaced the radiator module with a junkyard one. Fixed it right up

 

Cool thanks I've ordered a used fan module. but I also have another issue bothering me. I've jumped the switch to make both fans be on all the time, and the car still overheats.... Ive changed the head gasket, water pump, radiator, timing belt, and hoses. I don't know what is going on... I think I may just give up and take the car to a honda dealership, I spent around $2000 getting all that stuf done, at seperate times. I prolly could have just put in a whole new engine for that price. I also bought 2 new fan switches and the 2 temp sensors too. oh and also changed the thermostat twice.

 

Are you sure the car is actually overheating? Don't trust that stock 4g gauge, it acts funky when you have possible ground problems.

 

Possible ground problems eh?? is there a way I can get an accurate reading of the temperature? or how to fix this possible ground problem? If I can't trust the temp gauge, how will I ever know if my car is overheating before it just blows up? The car does have 212,000 miles on it........

 

If I installed a ground kit, would that help?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tonysaur &raquo;</TD></TR><TR><TD CLASS="quote">If I installed a ground kit, would that help?</TD></TR></TABLE>

No, just clean and inspect your stock grounds...make sure they make a good connection to bare metal on the frame. Don't forget the ECU ground on the thermostat housing.

Also try bleeding the cooling system for air bubbles.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tonysaur &raquo;</TD></TR><TR><TD CLASS="quote">Possible ground problems eh?? is there a way I can get an accurate reading of the temperature? or how to fix this possible ground problem? If I can't trust the temp gauge, how will I ever know if my car is overheating before it just blows up? The car does have 212,000 miles on it........</TD></TR></TABLE>

install a auto meter temp gauge but i would check grounds like others have said

 

jump the fan switch plug thats near the thermostat housing, where the bottom rad... hose meets the engine. Put the car on "on" first then jump it if the fan turns on then its the fan switch.

here read this https://honda-tech.com/zerothread?id=2012417

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LukieLuc &raquo;</TD></TR><TR><TD CLASS="quote">jump the fan switch plug thats near the thermostat housing, where the bottom rad... hose meets the engine. Put the car on "on" first then jump it if the fan turns on then its the fan switch.

here read this https://honda-tech.com/zerothread?id=2012417</TD></TR></TABLE>

Like I said before, I've done that and the fans WILL go on that way. Leading me to believe it is the fan switch. but then when I install a brand new switch, the fan still never comes on. I also replaced that fan control module near the ecu and am still having the same problems with both fan switches.