Heater does not work

2003 TOYOTA SEQUOIA
130,000 MILES
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RICHARD SIMPSON
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  • 3 POSTS
The temperature control knob works from max cool to hot but the control valve is not opening. I unhooked the cable and opened the valve manually, but the blend door is not working either so it still blows cold air. any help would be appreciated.
Jan 11, 2018 at 7:12 AM
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STRAILER
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Hello,

It sounds like you may have a fuse out (CIG or HTR), this is what I would check first. Here is a wiring diagrams for the air conditioner and the fuse panel locations and diagrams as well:

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

Check out the diagrams (below).

Please run this test and get back to us.

Cheers, Ken
Jan 12, 2018 at 1:39 PM
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RICHARD SIMPSON
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  • 3 POSTS
Sorry it took so long to get back with you I just got to where I could check the fuses. Both fuses are good and have power. I can pull the cig fuse and it has no effect on the problem the temp read out works from max cool to hot ,the mode changed from panel to floor. When I pull the htr fuse the only thing that doesn’t work is the blower everything else works according to the controls but still no control valve function or blend door operation. I am having trouble following the wiring diagrams but any other suggestions will be appreciated
Jan 24, 2018 at 10:00 AM
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RICHARD SIMPSON
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Any thing else that I can check
Jan 24, 2018 at 10:04 AM
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STRAILER
  • CERTIFIED EXPERT
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It sounds like the controller is out to me. I would see if the control head is getting power and ground to confirm the failure.

Here are more diagrams to help us see how the system works.

Please run some tests and get back to us.

Cheers, Ken
Jan 24, 2018 at 12:01 PM