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Re: 2003 Highlander AC/Heat problem
"Bruce L. Bergman" <blPYTHONbergman@earthlink.invalid> wrote in message
news:1caso299r22gkn5dvn8dmptji49capqv1t@4ax.com...[color=blue]
> On Sat, 23 Dec 2006 16:06:01 -0600, "Noon-Air" <Noon-Air@comcast.net>
> wrote:[color=green]
>>"Noon-Air" <Noon-Air@comcast.net> wrote in message
>>news:LbKdnTe2uJmVAxDYnZ2dnUVZ_tijnZ2d@comcast.com...[color=darkred]
>>> "thomaskblair" <thomaskblair@bellsouth.net> wrote in message
>>> news:W8gjh.9623$cB6.8883@bignews7.bellsouth.net...[/color][/color]
>[color=green][color=darkred]
>>>> My 2003 highlander switches between AC to Heat constantly. It is
>>>> acting
>>>> like the temperature controller is being moved between cold and hot
>>>> every
>>>> few seconds.
>>>>
>>>> Any ideas as to what I should check first?[/color][/color]
>
> First figure out exactly what's it's doing to give you the Hot-Cold
> swings, then you can figure out how to cure it - Is the AC Compressor
> running constantly, cycling on and off, or not running at all? Engine
> temperature gauge steady of bouncing? Heater hoses hot (open heater
> valve) or not? Can you see the heater valve linkage to tell whether
> it is cycling? How about the blend doors, Heat/Defrost/Air door or
> the Fresh/Recirc door?
>
> My first thought is the radiator coolant level is way low, and you
> have air pockets cutting the heat flow intermittently. If the cab
> temperature control panel is sending signals to the AC compressor and
> heater valve alternately, it could be the cabin temperature sensor is
> bad and giving it a comfort temperature target that keeps moving...
>
> Another thing that the dashboard controls like to do is get cold
> solder joints between the circuit board and the potentiometers and
> switches. If you can push on one corner of the Fan Speed Switch or
> the Temperature Slider and everything returns to normal while you are
> pushing, pull out the controls and resolder everything.
>
> Give us a bit more to work with here.
>[color=green][color=darkred]
>>> The Yellow Pages for a tech to straighten out the mess you made when
>>> you
>>> tried to install that new thermostat you got from Home Depot.[/color]
>>
>>Oops... sorry... wrong group :-)[/color]
>
> You are supposed to restrict the snarky one-liners to alt.hvac,
> where the norm is to treat everyone like they're trying to take the
> bread out of your mouth.
>
> Over here, we try to give honest and useful answers... ;-P
>
> --<< Bruce >>--
>[/color]
When this started the other day, whenever I turned the fan switch on, the
air was immediately hot, but if I turned the temperature control a 1/4 turn
toward heat and back to cold, the air would go back to being cold. The
constant change between hot and cold does not happen all the time, but the
above does.
Thanks for your help
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