2007 Prius Heat / AC Not Working

Discussion in 'Gen 2 Prius Main Forum' started by Devon Smith, Dec 25, 2020.

  1. Devon Smith

    Devon Smith New Member

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    I have a 2007 Prius with just over 192K miles. I've been driving with the heat on maximum temperature, maximum fan speed, and with the A/C button on, in order to prevent the windows from fogging up. Unfortunately the windows have ended up fogging up a few times over the last few days despite my best attempts, and so I've gone to turn the temperature from high to low, but when I do the system simply goes from blowing hot air to warm air, and will continue doing so for about 5 to 10 minutes before blowing cold. Alternatively, if I turn the fan off, and then back on, it will begin blowing cold air almost instantaneously. I'm hoping someone might know why it takes 5 to 10 minutes to go from hot air to cold air unless I turn the fan speed off and then back on in order to get it to blow cold almost immediately, and if the heat / AC is broken, or if I'm simply missing something?. Thank you!
     
  2. PriusCamper

    PriusCamper Senior Member

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    Are these symptoms a result of short drives or after a 1/2 hour of driving? Also accurately measuring temps coming out with thermometer or thermal cam is crucial. And is you car clean and empty or a cluttered mess, 'because a wet towel or something else could be source of window fogging? Also leaks in the roof seam and elsewhere could lead to a puddle of water in 12v battery or spare tire well that could be source of window fogging.
     
  3. Devon Smith

    Devon Smith New Member

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    Thank you for the expedient response and insight. The symptoms occurred after about a 45 minute to hour long drive. I will make it a point to check the temps coming out with a thermometer. Just out of curiosity, why is it important to check the temps coming out? The car is kept clean and empty. I will make sure to check the spare tire well and 12v battery to ensure no water is leaking in. Additionally, I forgot to mention in the original post that I was driving with the air set to recirculate... if that makes a difference with why it takes 5 to 10 minutes to go from hot air to cold air unless I turn the fan speed off and then back on in order to get it to blow cold almost immediately?
     
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    I would GUESS that having the blower fan on high speed puts too much air pressure on the temperature blend door- causing it to bind. It requires more force to move the door than the servo motor can produce. Turning the blower off relieves the bind, and the servo can then move quickly.

    Possible causes for persistent fogging; A/C doesn't work (A/C removes moisture from the air), clogged A/C drain, as mentioned before- external water leak (windshield, sunroof, back hatch), or possibly a seeping heater core.

    Posted via the PriusChat mobile app.
     
  5. PriusCamper

    PriusCamper Senior Member

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    For the fogging windows problem, not sure what the weather is like where you're at right now but maybe that could play a factor? I think there's lots of snow right now? Or is that further north? Because slushy snow can get into places that regular water can't... Or did you fill your car up with people who were walking in slushy snow?

    For the heater problem, there's an electric heating element that you could check the fuse on. Also checking the engine temperature can be done by using the hybrid assistant app on your phone. You just need one of these inexpensive devices to connect to your car: Hybrid battery diagnostic and repair tool for Toyota and Lexus Once you know the status of all that we could provide more advice.

    Also changing your cabin air filter has solved my issues at times and they only cost $8 if you know where to look: C35479 TOYOTA CHARCOAL CABIN AIR FILTER FOR TOYOTA PRIUS 2001 - 2009 | eBay
     
    #5 PriusCamper, Dec 26, 2020
    Last edited: Dec 26, 2020
  6. PGHtoolman

    PGHtoolman Junior Member

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    You should not use recirculation when trying to defrost the windows.

    texting from Luke's old jalopy Red 5
     
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  7. PriusCamper

    PriusCamper Senior Member

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    While true when you're the only vehicle on the road. If you're around a bunch of diesal trucks or cars with cold engines that just started up you're going to poison yourself way more with toxic air if you're NOT using re-circulation: Warmed up and raring to go: What happens when a car starts in the cold? -- ScienceDaily
     
  8. PGHtoolman

    PGHtoolman Junior Member

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    No I meant the setting on the controls. Not opening windows. Turn on your windshield defroster and the recirculation turns off.

    In the US unless you are shoving your nose up a tailpipes. You will be ok. Our cars are so efficient they could run on the exhaust of 1960s cars.

    texting from Luke's old jalopy Red 5
     
  9. PriusCamper

    PriusCamper Senior Member

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    Recirculate doesn't smell like other people's car exhaust as much as when it's not on reciirculate. Can't you smell the difference?

    Your response is alot like the proverbial frog in the pot of hot water on the stove... Because why jump out of the pot? It's not that hot... A little heat doesn't bother anyone, it's not like there's any risk of getting sick and dying, there's no risk of disease or death ever, right? Just compare the heat/air pollution to a time when the air pollution was worse and you'll never have a problem ever, right?

    Or alternatively, just like I was taught in my 7th grade chemistry class, if you smell something that's toxic immediately breathe out even if you're mostly out of air and wait to breathe in until you're away from the bad air. Been doing that all my life!!!
     
  10. PGHtoolman

    PGHtoolman Junior Member

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    The defroster works with hot fresh air.

    texting from Luke's old jalopy Red 5
     
  11. PriusCamper

    PriusCamper Senior Member

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    Yes it does, but you can switch it to recirculate manually and though it may be less efficient it's less toxic if you're in a city in traffic...
     
  12. PGHtoolman

    PGHtoolman Junior Member

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    Thank you.
    I am glad we could agree.

    texting from Luke's old jalopy Red 5
     
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