Heater hot or cold, nothing in between

[toyorgy]

[2007 4runner] My heater blows hot or cold but not warm. Does anyone know what is wrong with it?

 

[AuSeeker]

[2007 4runner] My heater blows hot or cold but not warm. Does anyone know what is wrong with it?

Possible bad or loose connection on the cabin air temperature sensor or it's dirty, which is most of the time the case, look on the trim panel just below the ignition switch you will see a group of small holes, the sensor is mounted on the back of the trim panel behind the holes, sometimes the holes get clogged with dust or the sensor itself is covered with dust, either will cause false temperature detection by the sensor, if you find that it's dirty use compressed air or a soft brush to get rid of the dust.

If that's not the issue then you could have a bad blend door solenoid, it's unusual for it to go bad where it only work at either hot and or cold but not in between, usually it would be stuck at one or the other setting/temperature

 

[Mantilgh]

Check to make sure you are not low on coolant and have air in the system.


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[toyorgy]

Thanks guys, I'll take a look at it today. At the bottom it starts off as "low" then the next temp is 66° which is when it blows hot air.