heater needs to be set to 80+ for heat after AC repair

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by rlaika, May 22, 2026 at 12:13 PM.

  1. rlaika

    rlaika New Member

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    Last month, a local auto shop replaced our 2006 Prius AC compressor and AC servo motor. Since then, we have to set the temperature control to the high 80s to obtain any heat. The local shop says the heater is working correctly; I say it isn’t, since previously we obtained heat when the temperature was set to the low 70s. I’ve dug around on PriusChat forums and haven’t found any solutions that directly address my circumstances, although perhaps air in the coolant might be an issue? Anybody have any ideas before I bring the Prius back to the shop again next week? Thanks!
     
    #1 rlaika, May 22, 2026 at 12:13 PM
  2. PriusCamper

    PriusCamper Senior Member

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    An AC creates cooling... It's 80 degrees in most of Oregon today and You're concerned about the heater (which is an entirely separate system) not working? Clearly you're a dishonest robot plotting to spam us in future posts. Or have I misunderstood and you have a reasonable logical explanation? :)
     
    #2 PriusCamper, May 23, 2026 at 3:37 AM
  3. Tombukt2

    Tombukt2 Senior Member

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    You're heater hoses to firewall should be quite warm three min after start up if this is case system making heat just fine. You not getting it on to cabin is another issue . Deal with later .
     
    #3 Tombukt2, May 23, 2026 at 6:53 AM
  4. ChapmanF

    ChapmanF Senior Member

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    First, I would check for any codes from the HVAC system. You can do that without a scan tool, if you scroll down to "Codes from the heat/air conditioning system" on this page:

    Blink (a/k/a Flash) Codes – How to. | PriusChat

    Next, I would watch A/C system live values using a scan tool, paying particular attention to what it thinks the interior cabin temperature is. It will only heat when your temperature setting is above what it thinks is the cabin temperature (unless you go to a temperature setting of which heats unconditionally).

    The cabin temperature reading comes from a sensor roughly above the driver's right knee.
     
    #4 ChapmanF, May 23, 2026 at 9:27 AM
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