How do I check if ECT switch is bad?
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Rep Power: 241 How do I check if ECT switch is bad?
My radiator fan hasn't come on for over a year, at least from what I know. I'm not experiencing any overheating strangly. I'm running Honda anti-freeze.
I just shorted the radiator fan to the battery and it starts fine. I found a troubleshooting guide for this, but the author wrote it poorly. Here's where I'm confused:
"Thermo sensor check
Short the contact on the connector going to the thermo switch to ground. This connection goes to the fan relay. (WHAT???? I don't understand what you're trying to say. Do I do this when the car is on?)
If the fan turns on, your thermo switch is most likely bad.
If the fan does not turn on and the fan was not turning on with the AC running, your relay may be bad."
I just shorted the radiator fan to the battery and it starts fine. I found a troubleshooting guide for this, but the author wrote it poorly. Here's where I'm confused:
"Thermo sensor check
Short the contact on the connector going to the thermo switch to ground. This connection goes to the fan relay. (WHAT???? I don't understand what you're trying to say. Do I do this when the car is on?)
If the fan turns on, your thermo switch is most likely bad.
If the fan does not turn on and the fan was not turning on with the AC running, your relay may be bad."
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Rep Power: 241 Re: How do I check if ECT switch is bad?
Wait, is he saying that I should stick a wire from the negative into the positive of the ECT switch? I think so...
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Rep Power: 241 Re: How do I check if ECT switch is bad?
Yup, fan come's on when I short it. I already checked the relay, fuse, and motor before this so it was down to the wiring or ECT switch. Should I buy a stock ECT or should I go for a lower TEMP switch?
Here is the troubleshoot guide: http://www.tegger.com/hondafaq/overh...heating-index/
Here is the troubleshoot guide: http://www.tegger.com/hondafaq/overh...heating-index/
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Rep Power: 257 Re: How do I check if ECT switch is bad?
switch the car on and short the two terminals of your ECT sensor connector. if the fans turn on, everything else is good. replace the switch. if not, check the relay in the underhood fusebox. I had a problem with my fans not turning on at all. it turned out being the switch after I had replaced the thermostat.
the only way to check the switch is to heat it up to 199 degrees (according to certain online manuals) and check for continuity. as i'm sure you imagined, it would be quite hot and not easily handled at that temp.
the only way to check the switch is to heat it up to 199 degrees (according to certain online manuals) and check for continuity. as i'm sure you imagined, it would be quite hot and not easily handled at that temp.
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Rep Power: 241 Re: How do I check if ECT switch is bad?
switch the car on and short the two terminals of your ECT sensor connector. if the fans turn on, everything else is good. replace the switch. if not, check the relay in the underhood fusebox. I had a problem with my fans not turning on at all. it turned out being the switch after I had replaced the thermostat.
the only way to check the switch is to heat it up to 199 degrees (according to certain online manuals) and check for continuity. as i'm sure you imagined, it would be quite hot and not easily handled at that temp.
the only way to check the switch is to heat it up to 199 degrees (according to certain online manuals) and check for continuity. as i'm sure you imagined, it would be quite hot and not easily handled at that temp.
Do you know if I need to drain the radiator fluid before thermo switch removal/install?
Last edited by Cleft_Asunder; 06-11-2008 at 07:02 PM.
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Rep Power: 241 Re: How do I check if ECT switch is bad?
Yeah but how do I know the switch is bad for sure? I NEVER overheat. It was 85 today, and I did all city driving. Temp is totally normal. Fluid level is perfect. How do I know I'm even reaching 194 degrees?
I don't want to remove the radiator fluid if the switch is still good. But again, the fan does not turn on when I hit A/C. Are they both supposed to turn on or not?
I don't want to remove the radiator fluid if the switch is still good. But again, the fan does not turn on when I hit A/C. Are they both supposed to turn on or not?
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Rep Power: 241 Re: How do I check if ECT switch is bad?
Source:
http://www.hondacarforum.com/honda-3...5-civic-2.html
"I just replaced the thermo switch, and the radiator fan *still* doesn't come
on, even with the AC switched on (the AC compressor fan on driver's side
does come on).
I measured the new thermo switch by putting an ohmmeter across the terminals
and lowering it into a pan of boiling water. After the switch closed I got 1
ohm of resistance. The old thermo switch read 8 ohms. So I guess it was bad?
I'm not sure what else it could be.... shorted one side of the thermo switch
connector to ground does make the fan come on while the engine is running.
There's nothing else in the circuit as far as I know.
The temp guage never rises above 1/3 level (so far). Tegger, you had asked
about the heat output in the passanger compartment. At times, it seems to be
normal. Other times, it seems to be cool, even when the temp setting is over
at max. Could this be due to a bad thermostat or something else?"
Reply:
Personally, I think you're barking up the wrong tree here. 1 ohm or 8 ohms
means nothing. If the temp gauge never gets past 1/3, the rad fan WILL NOT
START NO MATTER WHAT.
If you simulated the heavy stop-and-go traffic like I said for AT LEAST 5
MINUTES, and the temp gauge DID NOT RISE, then your engine IS NOT HEATING
UP ENOUGH to make the fan come on.
I do believe you have a bad thermostat. Replace with new **OEM** for $20,
then report back, BEFORE you spend bigger bucks on the thermoswitch.
http://www.hondacarforum.com/honda-3...5-civic-2.html
"I just replaced the thermo switch, and the radiator fan *still* doesn't come
on, even with the AC switched on (the AC compressor fan on driver's side
does come on).
I measured the new thermo switch by putting an ohmmeter across the terminals
and lowering it into a pan of boiling water. After the switch closed I got 1
ohm of resistance. The old thermo switch read 8 ohms. So I guess it was bad?
I'm not sure what else it could be.... shorted one side of the thermo switch
connector to ground does make the fan come on while the engine is running.
There's nothing else in the circuit as far as I know.
The temp guage never rises above 1/3 level (so far). Tegger, you had asked
about the heat output in the passanger compartment. At times, it seems to be
normal. Other times, it seems to be cool, even when the temp setting is over
at max. Could this be due to a bad thermostat or something else?"
Reply:
Personally, I think you're barking up the wrong tree here. 1 ohm or 8 ohms
means nothing. If the temp gauge never gets past 1/3, the rad fan WILL NOT
START NO MATTER WHAT.
If you simulated the heavy stop-and-go traffic like I said for AT LEAST 5
MINUTES, and the temp gauge DID NOT RISE, then your engine IS NOT HEATING
UP ENOUGH to make the fan come on.
I do believe you have a bad thermostat. Replace with new **OEM** for $20,
then report back, BEFORE you spend bigger bucks on the thermoswitch.
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Rep Power: 787 Re: How do I check if ECT switch is bad?
both fan should come on with a/c in use, ALL THE TIME otherwise the condenser does not get enough flow and your air wont be as cold. radiator fan only comes on periodically while driving, usually for 10 seconds at a time. our civics do not rely as much on the fan as other cars. i saw an older ford come in with broken radiator fan and the car overheated so bad, the entire overflow tank was empty from coolant boiling off. ive rarely noticed the fan kick on unless the car is at idle in warm weather 80F+ but it should come on. after driving for a while, park the car in the sun and wait 5 minutes at idle. the fan will come on at least once if its above 80F outside i promise. if it doesnt then you have a problem
Last edited by gearbox; 06-11-2008 at 09:38 PM.
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Rep Power: 241 Re: How do I check if ECT switch is bad?
both fan should come on with a/c in use, ALL THE TIME otherwise the condenser does not get enough flow and your air wont be as cold. radiator fan only comes on periodically while driving, usually for 10 seconds at a time. our civics do not rely as much on the fan as other cars. i saw an older ford come in with broken radiator fan and the car overheated so bad, the entire overflow tank was empty from coolant boiling off. ive rarely noticed the fan kick on unless the car is at idle in warm weather 80F+ but it should come on. after driving for a while, park the car in the sun and wait 5 minutes at idle. the fan will come on at least once if its above 80F outside i promise. if it doesnt then you have a problem
I will see if it comes on in really hot weather. I will attach some tape to it maybe to see.
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