Mechanics

I HAVE A LIMITED. TEMPERATURE CONTROL ISSUE

2003 Toyota Sequoia • 162,000 miles

When I turn the temperature control **** to max cold. The heater control valve goes all the way to the top and cold air blows. When I adjust the temperature off of "max". Even by just one degree. The heater control valve goes all the way to the bottom and hot air blows. So it seems that it is either all up or all down. I assume it should vary to allow cooler or warmer temperatures to come through heater core. I guess the heater control valve is ok and the control cable is ok. So is my problem the temperature control electronic parts are something different?
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Jimdonsmith
November 9, 2011.



In american cars they are actuators but in yours they are servo motors. I've included a pic see if they are working corrrectly, especially the air mix one


Hmac300
Nov 9, 2011.
Thanks for the quick response. Is there a way to determine if the problem is the servo or the actual control ****?


Tiny
Jimdonsmith
Nov 10, 2011.
If it's vacuum turn the control toheat and see if you are getting vacuum. If you are and it's not working then it's the servo. If it's electricyou'll have to do the same but use a test light or vom


Hmac300
Nov 10, 2011.
Ok. I still have no clue. I changed the air temperature control and the problem remains. What regulates the air mix servo? If it is only working from all hot or all cold. Then a relay, resister or some sort of module must tell it to stop in the middle to allow the air to mix to "warm". Any information would be greatly appreciated.


Tiny
Jimdonsmith
Dec 1, 2011.
It's controlld by the control unit that says hot/cold. If it's vacuum it's how much is sent to it and if it's electrical ther ewill b a module inside teh control unit for it.


Hmac300
Dec 1, 2011.
OK. Got it figured out. When I took car to dealership to have them repair the ignition switch, they unplugged the thermistor and never plugged it back in. It was located under the driver steering wheel behind the temperature sensor vent. I plugged it back in and it works perfectly. Thanks.


Tiny
Jimdonsmith
Dec 10, 2011.
Our pleasure. Happy to help. Closing thread.


Rivermikerat
Jan 27, 2012.