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Cooling fan not working?

Tiny
GARBADDAS11
  • MEMBER
  • 2005 TOYOTA COROLLA
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
I check fuses relay looks good. There is no power on the fan wiring coupler
i found there is no power in relay2 plug.
Saturday, October 3rd, 2020 AT 5:24 AM

32 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. Let's focus on why you don't have power on that relay. Also, which terminal do you not have power on? Take a look at the wiring diagram and let me know what you find on each terminal when the engine is running. You should have 12 volts on terminal 1 and then the PCM and pressure switch will close which will ground the relay and that is what turns the fan on. So we need to find out if we have 12 volts on terminal 1 and go from there.

Thanks
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Saturday, October 3rd, 2020 AT 8:38 AM
Tiny
NICKSCUD
  • MEMBER
  • 1 POST
  • 2003 TOYOTA COROLLA
  • 1.8L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 106,000 MILES
I have already replaced both radiator fan relays and this did not fix problem. When the A/C is turned on and dial set to coolest position this sometimes causes fan to come on, but not every time - result is engine runs very hot and/or in overheat position. Not sure what to do next. The fan runs, but not always. I thought relays were logical place to start, but they did not solve problem. What is next logical step? I want to fix problem but not keeping throwing parts at it. Since problem is intermittent it seems like it will be tricky to troubleshoot. Please help!
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Sunday, October 25th, 2020 AT 11:33 AM (Merged)
Tiny
JONNYB1963
  • MECHANIC
  • 252 POSTS
Hi Nick,

Thanks for visiting us. As to your problem. It be one or more of a few things. First thing as you stated that this was intermittent, I would start looking for loose or damaged wires, damaged connectors too.

Check the wiring between the fan fuse (30A) and the fan relay 1.
Then check the wiring of between the fan relays and the ECM.
The next thing I would check is the Engine Coolant Temperature Sensor.

Here is a schematic of the system layout.
See picture attached.

Jon
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Sunday, October 25th, 2020 AT 11:33 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Hello,

When the AC is on please check the fan motors for power. This will tell you if the motor is bad. Here is the wiring diagrams so you can see how it works and a guide to help you check for power:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

There is an AC pressure switch that controls the fan motors as well (P2).

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Cheers, Ken
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Sunday, October 25th, 2020 AT 11:33 AM (Merged)
Tiny
MIKE ROWE2
  • MEMBER
  • 1 POST
  • 2003 TOYOTA COROLLA
  • 1.8L
  • 4 CYL
  • FWD
  • MANUAL
  • 5,700 MILES
Fan will not run. Checked fuses changed relay. What else could it be?
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Hello,

It sounds like the fan motor is no good which is most common. Here is a guide to help you get the problem fixed.

https://www.2carpros.com/articles/replace-electric-fan-motor

Please let us know what happens, we are interested to see what it is.

Cheers, Ken
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BLESSING EWOBOR
  • MEMBER
  • 686 POSTS
  • 2001 TOYOTA COROLLA
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 232,543 MILES
Hello, the vehicle's radiator fan stop functioning, it only comes on when the vehicle A/C is put on. I searched for temperature switch, I didn't see anyone. I try to jump the temperature sensor wires but it had three wires, I just know of two wires so I ran.
What could be the cause? And could I get the circuit diagram?
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
I've attached the location and the test for the coolant temperature sensor/switch, also the diagrams. More than likely you have an ECT sensor issue, but the tests should be performed to verify this.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BLESSING EWOBOR
  • MEMBER
  • 686 POSTS
Thank you, but could you help me resend picture 3 and 4? It is somehow blur.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BLESSING EWOBOR
  • MEMBER
  • 686 POSTS
I said earlier that the temperature sensor that I saw on the engine has three wires or are they the same?
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BLESSING EWOBOR
  • MEMBER
  • 686 POSTS
The one you sent on the diagram has two terminals and can I jumped the wires to check if the fan would comes on?
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BMDOUBLE
  • MECHANIC
  • 1,139 POSTS
Shorting those two together will not give you the desired effect, just by disconnecting the sensor the fan should go to full speed because the resistance will be high, so high resistance will be interpreted as high heat to the ECM, thus giving a desired high fan speed. Either a fuse is blown, and or the fan is drawing too many amps.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BLESSING EWOBOR
  • MEMBER
  • 686 POSTS
Okay, thank you.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
BLESSING EWOBOR
  • MEMBER
  • 686 POSTS
Good morning, is there any test for the thermostat to know if it is stuck without removing it from the vehicle?
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
PONGC
  • MEMBER
  • 1 POST
  • 2000 TOYOTA COROLLA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 93,000 MILES
Radiator fan not working whlie temperature gauge is go up to the red during driving. But when I turn on the A/C, the radiator fan start to work and cool down the engine. The thermostat can able to detect the temperature that make the gauge works and the fan relay works.
So only thing is I have to turn on the A/C in order to turn the radiator electric fan on to avoid overheat on the engine. And unable to find solution.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Do you think the cts might be causing a problem? Can you check for codes?
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
Also check the fan switch, If you disconnect the fan switch and fans run, then fan switch is bad.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
PLZHELPMYCAR81
  • MEMBER
  • 1 POST
  • 1999 TOYOTA COROLLA
Air Conditioning problem
1999 Toyota Corolla 4 cyl Wheel Drive Type unknown Automatic 90500 miles

Hi my cooling fans wont come on, on my toyota corolla I replaced a couple relays on the fan no.2 relay and Fan no.1 relay and still they did not come on. How do I check to see if the relays are in working condition. I also replaced the cooling fan switch. I also jumped the fans to the battery and they came on so its not the motors.
Plz help. Basically I need to know how to check the relays.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
MMPRINCE4000
  • MECHANIC
  • 8,548 POSTS
If you disconnect the fan switch the fans should come on. If they don't, then the fan is bad (you checked that) or a relay(s) or the fan switch.

There are 2 relays that are marked fans, but the main engine relay also should be checked.

You can call a dealer or shop to see if they can check the relays.
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Sunday, October 25th, 2020 AT 11:37 AM (Merged)
Tiny
NATE B
  • MEMBER
  • 1 POST
  • 1996 TOYOTA COROLLA
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 165,000 MILES
I took my corolla to toyota dealer they said problem was the cooling temp sensor so I changed that but the cooling fan still will not come on if I hard wire it it works im thinking maybe cooling fan relay but it seems ok. How do you test a relay
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Sunday, October 25th, 2020 AT 11:38 AM (Merged)

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