theres 2 fans on the raditor as most know, and i just replaced the raditor (due to the old one leaking coolant). I had trans. fluid leaking and then the CEL came on because i completly lost all the fluid from the trans. So i got that all fixed and cleared the CEL, but now i have a problem with one of fans not coming on when the car is getting hot. The temp gauge will be just under half and rasing when the left or passenger side (if standing in front of the car) fan will turn on and try to cool down. THe right fan will not come on, although if i turn on the A/C it will come on. As soon as i turn off the a/c the right fan turns off. when i turn off the car, the left side fan comes on but the right side one does not... which if i recall they both used to turn on. The temp gauge will be at about 3/4ths and the left fan will turn OFF, and it will stay around there until i start to drive again. There is coolant in the raditor and in the overflow tank, and the upper hose gets hot so i believe the coolant is flowing thru it. I have an OBD II interface and the software, and i was told by my neighbor who used to work for honda to look at the temp in the software compared to the temp on the gauge and see if they seem consistant. He also told me to replace the thermo? Anyone else know what i could do?

 

one fan is your radiator fan, the other is your a/c fan. only the radiator fan will come on if you're not using the A/C. this is normal.

 

not true, both used to come on when the car was hot and i turned it off. It worked for a split second and then it shut off.

 

not in my experience. but that's fine. good luck with your problem.

 

what year do you have? maybe they are different. I know for a fact mine used to both turn on, wheather they were both supposed to or not

 

Here's a link to a PDF file that is the schematic you need..
http://members.troublecodes.net/hondadude/AC2of2
The fan control unit [behind the glove box] should provide a ground path to turn on the condensor fan relay, when the temp sensor calls for the main fan to run.
Yes you are CORRECT, BOTH FANS SHOULD RUN.

 

well.. i added some more coolant today, and let the air drain out and both fans came on, so i think the thermostat was telling it that it wasn't as hot as it was and therefore it didn't need to be cooled, although one fan was coming on while the other wasn't. I will be adding more coolant because i still am not convinced the radiator is full yet. I was told i would be seeing the coolant rushing past if i had the top off, but when i started the car with the cap off the raditor the coolant wasn't moving.

 

You will only see the coolant circulate after the T-stat opens. [hot hot hot] You should bleed out the air in the block thru the 12mm bleed screw at the T-stat housing; keep pouring in coolant to the radiator till it comes out the bleed screw.

 

will do. thanks

 

same with my car. the right fan isnt cooling my radiator down so i end up overheating when im idle. someone help?

 

make sure you have plenty of coolant, i found that that was my problem. I also think i had air bubbles in the raditor so it wasn't telling the car the right temp. But try adding coolant first.