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Discussion Starter #1
Hi.

New to the mkiv, just got it. And my climate control is only blowing cold, or hot air. There is no middle settings. Last owner told he had changed the unit itself, but no changes. The AC works. Where should i start looking?

thanks!
 

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Garage Queen Club
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Run the diagnostics from the controller (you hold down two buttons while turning key ON). There is a description in the service manual linked in various places on this forum. Blinking lights will inform you of any issues with sensors or actuators. Start there.
 

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Discussion Starter #4
Hi, thanks for your replay. I have the Aem v2 ECU, so dont think it will work..
 

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Discussion Starter #5 (Edited)
It could be a faulty heater valve if the control unit is good.
Will look into it, thank you! But if the valve is faulty, shouldnt i get only cold, or warm air then? you see when i turn the heater just a little over the coldest position it gets superhot.
 

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Hi, thanks for your replay. I have the Aem v2 ECU, so dont think it will work..
Has nothing to do with the AEM. It is the diagnostics of the HVAC unit on your dash. Please try to read the manual, it has everything you need there and high likely hood that you'll find your answer!
 

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Discussion Starter #7
Has nothing to do with the AEM. It is the diagnostics of the HVAC unit on your dash. Please try to read the manual, it has everything you need there and high likely hood that you'll find your answer!
Okey thanks, ill check it and report back soon! :)
 

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Discussion Starter #8 (Edited)
Did the diagnostic, thanks Dre99gsx. Got 2 error codes. room temperature sensor circuit, and solar sensor circuit. both codes have A/C amplifier, or Harness or connector between solar sensor and A/C amplifier in common, any tip?
 

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Toyota MasterTech
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before going crazy into trying to diagnose these...make sure they are plugged in...if you just got the car, the previous owner might have left one unplugged if they had some interior out...just a quick check...
 

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Discussion Starter #10
before going crazy into trying to diagnose these...make sure they are plugged in...if you just got the car, the previous owner might have left one unplugged if they had some interior out...just a quick check...
good tip right there sire! :) im pretty sure they are connected since i had the dash panel off while changing the reciver. But i will dobbelcheck!
 

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Discussion Starter #11
what component makes the air mix servo motor to stop at set temprature? since i can hear it glide all the way from hot to warm, or warm to cold it might be helpful to know when i start the search :)
 

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Did the diagnostic, thanks Dre99gsx. Got 2 error codes. room temperature sensor circuit, and solar sensor circuit. both codes have A/C amplifier, or Harness or connector between solar sensor and A/C amplifier in common, any tip?
Solar sensor usually gives an error if the sun is not shining on it, disregard. Room temp sensor fault can be an issue since it is needed for correct AUTO-temp mode. There is another mode where you can test all the operations of flappers and motors as well.

For the room temp sensor, could simply be a bad sensor. I would suggest removing it and testing it, and go from there, It should be easy to get to.
 

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Stock Twins King
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Run the diagnostics from the controller (you hold down two buttons while turning key ON). There is a description in the service manual linked in various places on this forum. Blinking lights will inform you of any issues with sensors or actuators. Start there.
WHAT?..This is something new to me!! Please explain this method of obtaining these codes...You push 2 buttons on the HVAC unit? and I thought I knew everything about this too...

Stu
 

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Discussion Starter #14
Solar sensor usually gives an error if the sun is not shining on it, disregard. Room temp sensor fault can be an issue since it is needed for correct AUTO-temp mode. There is another mode where you can test all the operations of flappers and motors as well.

For the room temp sensor, could simply be a bad sensor. I would suggest removing it and testing it, and go from there, It should be easy to get to.
I let you know when i figure out. thanks for helping :))
 
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