HVAC (AC) wiring diagrams please?

Tiny
LEE1977
  • MEMBER
  • 2014 FORD F-150
  • 3.5L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 80,000 MILES
AC blower does not work on max speed. New resistor, motor and cable. Works on all other speeds. When max speed is selected, it blows for a moment and shuts off until a lower speed is selected. Old resistor had signs of overcurrent on one of the pins. That is why I replaced all components. System used to shut off at all speeds. Now, just highest setting fails.
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Tuesday, August 7th, 2018 AT 5:28 PM

34 Replies

Tiny
KEN
  • ADMIN
Hello,

It sounds like the HVAC control head is losing signal, but to be sure here are the wiring diagrams so you can see how the system works and a guide on how to test it. If it tests bad I would try a used control head so you might need not to reprogram it. If so it will cost about $130.00 at the shop. Also, when you say resistor you mean the motor speed control? Were the parts OEM?

https://www.2carpros.com/articles/how-to-check-wiring

Check out the diagrams (below). Please let us know what you find.

Cheers, Ken
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Thursday, August 9th, 2018 AT 3:19 PM
Tiny
LEE1977
  • MEMBER
No, parts were O'Reily. Yes, by resistor, I mean the motor speed control.
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Thursday, August 9th, 2018 AT 4:28 PM
Tiny
KEN
  • ADMIN
It sounds like the speed controller is out again so you may have got a bad one. Try to take it back and if the new one works then you know what the problem is.
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Friday, August 10th, 2018 AT 10:55 AM
Tiny
LEE1977
  • MEMBER
Replaced the resistor again today (third time) and the problem still exists. Although, I may have narrowed it down. It only shuts off when the recirc is on at the highest setting. Almost as though there is a restriction in the duct and it causes the blower to pull too many amps and trips.

If the recirc is off, the fan works on all settings.

Any thoughts?
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Sunday, August 12th, 2018 AT 6:58 PM
Tiny
KEN
  • ADMIN
When the blower is on high and working can you feel the wires going to the blower motor to see if there are warm?
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Monday, August 13th, 2018 AT 12:55 PM
Tiny
KHALL60@Q.COM
  • MEMBER
  • 2012 FORD F-150
  • 0.5L
  • V8
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
Radio was cutting in and out and now only flashes time, the AC will work on the defrost set on cool or heat but not in AC mode? Just had engine replaced, the cluster and battery.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KEN
  • ADMIN
Hello,

It sounds like the radio is going out. To confirm here is a guide to help check the power and grounds to confirm the failure with the radio wiring diagrams so you can see how the system works:

https://www.2carpros.com/articles/how-to-check-wiring

For the climate control do you hear any clicking under the dash when the system is on? Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KHALL60@Q.COM
  • MEMBER
So we were having trouble with the oil pressure and they replaced the battery, the cluster panel. We had trouble with the cams in the engine and the engine had to be rebuilt. It was a couple of weeks later the radio started to cut in and out. Took it back to see if wiring was messed up as they used my old wiring harness. They said no. And yes, there is now a clicking when you turn on the AC or heater. Then it got worse and the AC cool or heat started the clicking noise. So we quit using it. I am able to use the heat and air through the defrost button, so I know the AC and heat works just not through the climate button, and radio and disk player is now non fictional. So should I take it back and have them check this connection? Would take to different dealership. As this one had it for four months. Thank you for responding. Kris
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KEN
  • ADMIN
These problems maybe not related to the engine work, it sounds like the radio has gone out if it has power and ground. The ticking noise is because the mode actuator needs to be replaced. here is a guide that will walk you through the steps with diagrams and instructions on how to replace yours:

https://www.2carpros.com/articles/replace-blend-door-motor

Here are all blend door actuator locations so you can see how to replace them and how the system works. Please let me know whats happens.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
JOSUE RIVERA CLAUDIO
  • MEMBER
  • 2011 FORD F-150
  • 3.6L
  • V6
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
I took my truck to a key-maker. After all copies where made and the setting where reset to add this two keys as the only administrative keys for the truck, the truck started showing a message that say battery saver mode and the truck AC did not turn on at all. (Does turn on like you press the button and no light come up). It seems to me like the AC climate control does not have power but the radio works fine, the 12 volts outputs charge my phone and all the instruments in the cluster work as well with the exemption of a battery light coming up right before turn in on the truck. I took the battery to three different auto part in order to be check and battery was 100% all three times. Also check the alternator and is charging the battery well. I don t know if the reset had something to do with this. I when back to the key-maker and he reset it again and it still doing the same thing. Call for dealership and they want to charge $180.00 just to run the diagnostic. Does anyone has this same problem?
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KEN
  • ADMIN
Hello,

Can I ask if the security light is flashing when you try to crank it over? What happens when you use the original key?

Lets run the codes to see what come up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
JOSUE RIVERA CLAUDIO
  • MEMBER
Hello,

Thank you for your reply. The truck does the same thing with both keys. If by security light you mean the red light that come on when I lock the truck, no I don t see a security light blinking. Everything in the panel work fine except the climate control unit as you can see in the video. Even the 12 volts outlets work fine. I have check the fuse one by one three times during this past weekend and today I did it again all are good. (Fuse box in the passenger side and fuse box in front of the engine). By the way I changed the battery today and still does the same thing.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KEN
  • ADMIN
Thanks for the video it helps us see what's going on. It looks like the HVAC module has gone out but to be sure lets test the power and ground to the module. Here is a guide and the HVAC module wiring diagrams so you can see how it works:

https://www.2carpros.com/articles/how-to-check-wiring

A HVAC/CAN scan will tell us as well

https://youtu.be/InIlnsjOVFA

If the power and grounds are good I would try a used/rebuild HVAC unit. Check out the diagrams (below). Please let us know what you find.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
JOSUE RIVERA CLAUDIO
  • MEMBER
I m follow your suggestions and I bought a used climate control unit. As soon it arrives I will install it and let you know if the problems was fix or not. Thank you for everything.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KEN
  • ADMIN
Okay please let me know what happens :)
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
JOSUE RIVERA CLAUDIO
  • MEMBER
Good afternoon Ken,

I just got the new/used climate control unit delivered today. I installed the unit and still no power what so ever. What should I check next?
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
JOHNHEAT1
  • MEMBER
  • 2009 FORD F-150
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 83,500 MILES
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.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KEN
  • ADMIN
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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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
KEN
  • ADMIN
Do you have power at fuse #f46? Here is guide to help and the fuse location as well:

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

Check out the diagrams (below). Please let us know what you find.
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)
Tiny
JOHNHEAT1
  • MEMBER
Ken what do you mean by initialized?
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Thursday, April 15th, 2021 AT 1:55 PM (Merged)

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