Temperature controls not working?

NICHOLS1089

MEMBER
2002 TOYOTA SEQUOIA
4.7L
V8
4WD
AUTOMATIC
188,000 MILES

So last week I attempted to change the temperature controls from the AC on to OFF. I couldn't change it using the controls. I heard the rear AC on so I reached back from the drivers seat and pressed OFF with no results. Air was still blowing from the front and rear vents. I attempted to take the negative battery terminal off and waited 10 minutes with hopes of the system resetting. This only made the air turn off. Now none of the controls work and I can't turn the air or heat on or off. What could be causing this?

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

So, when you try to turn it on now, does the switch light up? Or shows the display?
First you want to make sure that the fuses are good.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If the fuse checks out, then it could be due to a faulty HVAC control module.
Another possibility is a bad switch. These switches are integrated using and one can impact the functionality of the other one.

I have attached diagrams below for your reference.

Please let me know what you find or if you have any questions.
Thank you.

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