No heat

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ANDREW BERMAN, Apr 29, 2025 at 8:09 PM.

  1. ANDREW BERMAN

    ANDREW BERMAN Junior Member

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    My 08 base is driving me absolutely insane and I want to get rid of it..

    Haven’t had heat for while replaced the thermostat still nothing, found I had a plugged auxiliary pump cleaned that out and also changed another pump as I had a P1121 code. I drained the system bled all the air out and still no hot air lower and upper lines are hot, lines going to the auxiliary pump are hot, from the auxiliary pump to the car and return are cool , multi metered the pump and it’s showing voltage so I’m guessing the pump still works.
    I switched through the heat locations and all are moving fine just no heat.
    Scan tool shows car getting to 205 then fan kicks on and drops to 190’s but no heat

    Anyone with suggestions on what do check next so I can try to get my car back on the road?
     
    #1 ANDREW BERMAN, Apr 29, 2025 at 8:09 PM
  2. MAX2

    MAX2 Senior Member

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    You say that the pipes to the heater radiator in the car are both hot. Is the heater radiator hot to the touch?
    If there is a plug inside the radiator, then the hot coolant will not circulate through it and it is necessary to eliminate the cause of the plug, flush the heater radiator.
     
    #2 MAX2, Apr 29, 2025 at 11:09 PM
  3. dolj

    dolj Senior Member

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    ... and when MAX2 says plug, he means blockage. This was my thought, too. Either that or the air blend door under the dash is not working. That should give a B14xx error code, I believe, if that was the problem.
     
    #3 dolj, Apr 30, 2025 at 12:11 AM
    MAX2 likes this.
  4. MAX2

    MAX2 Senior Member

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    There may be an airlock in the heater radiator, or debris from hoses or leak-eliminators may have accumulated. Channels with impaired circulation inside the heater may not allow coolant to pass through. But it may also be that the dampers are jammed. Then the heater heating is localized and does not reach the consumer.
     
    #4 MAX2, Apr 30, 2025 at 12:32 AM
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