Radiator fan not working

Tiny
PAULNGUYEN2905
  • MEMBER
  • 2006 HONDA CIVIC
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
Hi How are you doing sir?I have been working on my Radiator Fan for many months but I can't fix it. I have check the motor by wiring the positive and negative on battery. I changed Radiator Fan switch on Radiator below and Relay on the location 15. I dont know anything else to work. I really need your help sir because it is about summer
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Thursday, April 23rd, 2015 AT 2:46 PM

27 Replies

Tiny
HMAC300
  • EXPERT
It sounds like you have checked almost everything.... use a test light and check the 2 fuses in the diagram to be sure they are good

Heres a guide on using a test light

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester
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Friday, April 24th, 2015 AT 7:54 AM
Tiny
PAULNGUYEN
  • MEMBER
I dont understand a lot about electricity sir. Can u just tell me what I should do. Someone wire the Radiator Fan to Manual switch, but it is not last for long time if it keep running. But I read on civic page that someone says that Radiator fan works whenever the engine reach 200F. If not, just A/C Fan working. Is it true how Radiator Fan on honda civic working.I used to own honda fit.2 fans work completely at the same time when engine starts.
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Friday, April 24th, 2015 AT 10:26 AM
Tiny
HMAC300
  • EXPERT
A/c fan works only when a/c is on.
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Friday, April 24th, 2015 AT 12:19 PM
Tiny
JEREMY ABSHER
  • MEMBER
  • 1998 HONDA CIVIC
  • 4 CYL
  • 2WD
  • MANUAL
  • 200,000 MILES
The other day it started to overheat. The radiator fan is not coming on. With alligator clips I connected the radiator fan directly to the battery and it started immediately so I know its good.

Next, I checked the Cooling Fan Relay switch/fuse and it is good.

After watching some Youtube videos I thought it was the Radiator Coolant Fan Switch so I bought one from

(pictured here http://shop.advanceautoparts.com/p/carquest-by-bwd-coolant-fan-switch-tfs600p/18970366-P?

vehicleIdFromReq=39784&isAllVehicle=false&vehicleIdSearch=39784&searchTerm=tfs600p&showTitle=)
and replaced it. That did not work.

Now I am thinking it is the engine coolant temperature sensor. However, I cannot seem to be able to find where that is to replace it.

Can anyone help tell me where it is or do you think it is something else?
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Saturday, June 22nd, 2019 AT 3:06 PM (Merged)
Tiny
RIVERMIKERAT
  • MEMBER
I would check continuity on the wires between everything. Start with checking for power to the fan and a good ground. Then work back. Here is an image showing sensor locations. I have also added the schematic for the cooling fan circuit.
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Saturday, June 22nd, 2019 AT 3:06 PM (Merged)
Tiny
STRAIGHTROADTOSUCCESS
  • MEMBER
  • 1993 HONDA CIVIC
  • 4 CYL
  • FWD
  • MANUAL
  • 272,078 MILES
Hello!
My 1993 Honda Civic keeps overheating. I have scoured the internet to find the solution but have always come up with the same basic answers. Relay in the underhood fusebox (fine), cooling switch on the thermostat housing (fine), thermostat (for overheating, but still fine), fan motor (fine).

I believe it may be a wiring problem but it seems unlikely. How do I jump the switch to the fan motor? If you can jump it from there, why is there a relay at all? I will rewire the relay and switch if necessary, but they join with 50 or more wires and don't want to take the chance of using the wrong wire.

I wired a rocker switch to turn my fan on but since my finger is not a temperature switch, there is no guarantee of correct timing of the fan. This is not a head gasket/core plug problem. I do not have AC.

This is definitely some sort of electrical problem. Usually, wires don't just "go dead". I do all of the work on my car myself, and will have no problem understanding (though maybe through more research) very advanced technical information. What can I do here? If I wire the fan directly to the switch on the thermometer housing, will it run all the time? Will it have a problem considering that the relay will be unused? Or is the relay used as the power supply for the switch? Or is the relay "a delay mechanism"?

I have a Haynes manual but the information is limited. I also have a mechanics detailed manual but finding specific information is very difficult and I have no luck.

I don't mind wiring the fan it to the switch or relay, I just don't want to do anything dangerous (electrical fire, damage of electrical parts from bypassing important parts, etc.)

I thank you in advance, information on this particular subject seems nowhere to be found, as they all seem to only go up to relay, switch, motor, thermostat, radiator & cap. For the guys who have done all of that, I hope we all can get an answer to save these people money!

Thank you
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Saturday, June 22nd, 2019 AT 3:06 PM (Merged)
Tiny
MILLARDPRATT
  • MEMBER
Having the very same problem with my 1993 Honda
Civic DX. Radiator Fan will not come on, replaced radiator, Thermostat, cooling fan relay, and Radiator thermometer. Pulled the cooling fan replay from the fusebox and straight wired it to it and it came on, so I know the fan is good.
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Saturday, June 22nd, 2019 AT 3:06 PM (Merged)
Tiny
KHLOW2008
  • EXPERT
Hi straightroadtosuccess and millardpratt,

Just some basic understanding before we get to resolving the problem.

The relays are for transfering power from the battery to the fans and the fan switch does not have the capacity for the amount of current to pass through.

Ok to the problem.

To jump the fan switch wire, disconnect if from the switch and use a paper clip or wire to bridge the connection.

Turn ignition swtch to ON and fan should work. If fan does not work, the wiring circuit or relay is at fault.

Let me know what you find and whatever info you need, I will try to get them for you.

I believe we can solve this problem without any modifications.
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Saturday, June 22nd, 2019 AT 3:06 PM (Merged)
Tiny
HEHERSON
  • MEMBER
Ur right mr khlow2008 same problem before with my honda civic esi 94.I replace all mention above but still. Den I decided to replace the radiator with new one. But still the same. You know what?I change the engine oil(castrol) and accedentally solve the problem. Until now its working good. No overheat at all. What an incedent hehehhe.
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Saturday, June 22nd, 2019 AT 3:06 PM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 2001 HONDA CIVIC
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 96,000 MILES
2001 Honda Civic mileage: 96,000. Some time ago, I noticed that our Civic was running hot (not overheating yet) and the electric fan didn't turn on. Recently I replaced the thermostat, radiator cap, radiator fan thermo switch but the fan still wouldn't turn on. I know it works because shorting the thermo switch wires turns it on. It normally runs with the temperature parked around center of the scale but in slow traffic will rise to 3/4 scale. Should the fan turn on then? My Haynes manual doesn't show full electrical diagram and I am not sure if only the thermo switch turns the fan on. Some models had relay also.
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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
The radiator fan normally turns on after the temperature is past on the gauge. You may have a faulty thermo-switch. In addition, if you have a blown head gasket it would allow exhaust to get into the cooling system, which in turn would fool the thermo-switch.
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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
EFUJISHI
  • MEMBER
  • 1998 HONDA CIVIC
  • 135,000 MILES
1998 Honda Civic LX- radiator fan does not work. Replaced radiator fan switch- still not working. Also, water temp gauge runs hot.
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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
FIXITMR
  • MEMBER
Did you test fan itself?
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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
EFUJISHI
  • MEMBER
Yes. Fan worked when I used paper clip to connect terminals that leads to fan switch. Now, when I did the same test- fan does not work.
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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
FIXITMR
  • MEMBER
So repeat test fails? Check fuses again? Or repeat clip test and tap on fan to see if it starts?
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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
JESUSBRISENO
  • MEMBER
  • 1991 HONDA CIVIC
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 150,000 MILES
The cooling fan is not working, but when I turn the a/c on both of them come on, Can u tell me where is the relay and what also can be wrong if changing the relay dosent help. Thanks
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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Test the coolant temperature sensor and if it has an engine coolant temperature sending gauge/switch check it too. Rel see below

Its located at right front corner of engine compartment


http://www.2carpros.com/forum/automotive_pictures/12900_fan_relay_7.jpg

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Saturday, June 22nd, 2019 AT 3:07 PM (Merged)
Tiny
APETERSON1221
  • MEMBER
  • 2004 HONDA CIVIC
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 245,000 MILES
The radiator fans only run when the heat or air conditioning is turned on. They do not run if the car is just idling. Is it the thermo switch?
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Friday, August 9th, 2019 AT 5:46 PM (Merged)
Tiny
HMAC300
  • EXPERT
Check the things in pic like temp sensor the fans should come on when a/c is on so they are good. It could be the multiplex unit under dash as well. If this is a hatchback or hybrid then the wiring isn't really correct.
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Friday, August 9th, 2019 AT 5:46 PM (Merged)
Tiny
CES760
  • MEMBER
  • 2003 HONDA CIVIC
  • 4 CYL
  • 2WD
  • MANUAL
  • 182,000 MILES
Where do I find the cooling fan switch? Any idea why is cooling fan not working? I just replaced my thermostat and still over heats.
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Friday, August 9th, 2019 AT 5:46 PM (Merged)

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