A/C will switch from max A/C to just the regular hi speed

2009 FORD F-150
83,500 MILES • 4.6L • V8 • 2WD • AUTOMATIC
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JOHNHEAT1
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When on the A/C will switch from max A/C to just the regular hi speed on its own, and then come back on to max A/C again and sometimes it goes to defrost on its own, air is cold but switches back and forth on its own.
Jul 15, 2018 at 2:59 PM
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STRAILER
  • AUTOMOTIVE REPAIR CONTRIBUTOR
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Hello,

This sounds like the controller is bad causing the problem you have described. Here is a wiring diagram for the system so you can see how it works and the panel removal instructions. You can see the compass is tied to the HVAC system. I would try a used unit to see what happens use may need to get it initialized.

Check out the diagrams (below). Please run some tests and get back to us.

Cheers, Ken
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Apr 15, 2021 at 1:55 PM
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JOHNHEAT1
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Ken what do you mean by initialized?
Apr 15, 2021 at 1:55 PM
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STRAILER
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When you install an electrical component sometimes it must be initialized much like when you add a computer component, same thing. Most shop can do it for about $130.00.
Apr 15, 2021 at 1:55 PM