2005 CHEVROLET OPTRA
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ROCHJOHN19
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sir gud day.. i have chevrolet optra 1.6 A/T 2005 model. my engine cooling fan is not working when the AC is off. but when the AC in on it runs both.. the technician told me that the model of my car is when you turn off the AC the engine fan does not work.. only if i turn on the AC.. is that true? he advice me to have a manual switch of the cooling fan. so if ever i am not using the AC my engine not overheat.. IS IT OKAY SIR? I notice both fan running slow than usual even the AC in on.. and my aircon did not make enough cool.. is that connected with may cooling fan?

thanks.. more power!
Oct 25, 2012 at 10:44 AM
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RIVERMIKERAT
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He's partly right. Turning on the AC automatically turns on the fan, no matter what. But, there is a temperature sensor in the engine or head mounted on the side or top that detects how hot the engine is running. This sends a signal to the computer which determines whether the fan is required to cool the engine coolant.
Oct 25, 2012 at 1:51 PM
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RIVERMIKERAT
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And it sounds like the AC needs to be recharged.
Oct 25, 2012 at 1:51 PM
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ROCHJOHN19
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thanks for the response sir..

i compare my chevy optra to other car when the AC is off. even my engine is to hot still my fan not working but other one works.. do you think sir my temperature sensor is not working?
Oct 26, 2012 at 3:21 AM
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RIVERMIKERAT
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It's either the temperature sensor, the fan relay, the fan fuse, or the fan. See if the fan has power. If yes, replace it. If no, trace the wire back to the next location (temp sensor or fan relay). See if there is power. Keep going until you find the faulty part.
Oct 27, 2012 at 2:52 AM
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ROCHJOHN19
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only if the AC is on the fan has power, but when the AC is off it will not work.. how do i check sir if there is a power? yes sir i will check all that posible problem.. i will comeback to you sir.. thanks..
Oct 27, 2012 at 1:59 PM
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ROCHJOHN19
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one thing sir.. is it okay if i direct the power of fan when i start the engine? i mean everytime that the AC is off the fan is always on..
Oct 27, 2012 at 2:05 PM
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RIVERMIKERAT
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It sounds like the temperature sensor is bad. If the AC turns the fan on, most likely the fan relay is good. If you have a meter or test light, get the car up to operating temperature and see if there is power to and from the temperature sensor. You car isn't available in the US, so I can only guess at its location. It'll be somewhere on the head or the engine block, probably in front.
Oct 27, 2012 at 4:37 PM
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ROCHJOHN19
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sir good day! ive already checked all the posible problems.. one thing i noticed that my a/c and auxillary fan runs slower than usual. What is the problem sir? Thanks..
Jun 16, 2013 at 10:32 PM
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RIVERMIKERAT
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A slow running fan could be a bad relay or a bad fan.
Jun 17, 2013 at 8:23 AM