2003 Ford F-150 AC/Heat not working

Tiny
EAUSTIN
  • MEMBER
  • 2003 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 73,000 MILES
I noticed my ac was not working and took it to have it serviced. They did a routine ac service and added one can of R13 but it still did not work. I then checked my heater and it will not work. Both blow out air it is just whatever temp it is that day. The compresser works if I jump it over, check all the fuses and relays in distribution box under the hood. Any ideas would be greatly appreciated.
Sunday, July 18th, 2010 AT 4:54 PM

19 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Have you checked the blend air door? Is the AC compressor cycling? If both are not working, chances are the blend air door may be stuck.
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Sunday, July 18th, 2010 AT 10:21 PM
Tiny
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The only way the compressor will cycle is if I jump it over, how do I check the blend door?
Thanks for your help.
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Tuesday, July 20th, 2010 AT 5:31 AM
Tiny
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The blend door and compressor are not related. The blend door is near the heater core and opens and closes based on if you want heat or AC.

As far as the compressor, how are you jumping it? Are you running power directly to the clutch? If so, have you checked the AC cycle switch?
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Tuesday, July 20th, 2010 AT 10:40 PM
Tiny
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I jumped it over by unplugging the connector and putting power from the batter to the terminal.
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Wednesday, July 21st, 2010 AT 5:23 PM
Tiny
EAUSTIN
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I also jumped over the two other switches I found on the line and the compressor would not come on with either of them juped over.
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Wednesday, July 21st, 2010 AT 5:24 PM
Tiny
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Based on what you said, I am inclined to say the cycle switch is bad. Have that checked and let me know what you find.

Joe
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Wednesday, July 21st, 2010 AT 11:44 PM
Tiny
EAUSTIN
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I will thanks for your help.
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Thursday, July 22nd, 2010 AT 6:05 PM
Tiny
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  • MECHANIC
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Let me know what you find.

Joe
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Thursday, July 22nd, 2010 AT 11:52 PM
Tiny
EAUSTIN
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  • 10 POSTS
Ok, had a blown fuse when issue started, replaced it could not get anything to work. Mechanic found a blown fuse today and tracked power to control panel and said I would have to come back. Everything is working fine now. So it seems all of the main components are working. Any idea what could be causing the fuse to blow? Thank you for all of your help.
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Saturday, July 24th, 2010 AT 10:22 AM
Tiny
EAUSTIN
  • MEMBER
  • 10 POSTS
Ok this is what I have it narrowed down too, the compressor is is not disengaging it will run the entire time the ac is turned on until it blows the #5 fuse under the dash. Any ideas?
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Saturday, July 24th, 2010 AT 1:45 PM
Tiny
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Replace the cycle switch.
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Saturday, July 24th, 2010 AT 11:16 PM
Tiny
EAUSTIN
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Thank you so much for your help.
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Sunday, July 25th, 2010 AT 7:29 AM
Tiny
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I'm happy to help. Let me know if that fixes it for you.

Joe
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Monday, July 26th, 2010 AT 12:38 AM
Tiny
EAUSTIN
  • MEMBER
  • 10 POSTS
Well, it worked great for about a week then it started blowing fuses again. I appreciate your help, just not sure what else to do for it.
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Saturday, August 7th, 2010 AT 8:28 AM
Tiny
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That isn't good. Have you checked the wiring to the cpmpressor clutch?
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Saturday, August 7th, 2010 AT 11:15 PM
Tiny
EAUSTIN
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I looked it over and did not see any problems, took it to the dealer today and after about 2hrs he could not get it to blow the fuse. He checked the wiring all the way back to the power box. He looked dumb fuzzled. His idea was to buy a box of fuses and bring it back when it would blow them right away or finally melted the part causing the problem.
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Monday, August 9th, 2010 AT 8:05 PM
Tiny
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That's great advice. Drive it until something catches fire or it blows another fuse. Good lord, I wouldn't have a job. Did he check how much power the compressor clutch is drawing? If it is drawing too much current, it could have caused the problem with the cycle switch.

Let me know.

Joe
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Tuesday, August 10th, 2010 AT 11:01 PM
Tiny
EAUSTIN
  • MEMBER
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I'm not sure what he checked, but I got to thinking.
Seems like if it was the ac system it would blow the ac fuse under the hood. I then starting to check the other systems off this fuse. The fuse only blows when the truck is put in reverse. You can use any of the other systems, cruise control, ac, or park the truck and turn it off and back on and it is fine. AC can run for hours no problem. Put it in reverse and the fuse blows. Now I gues I need to start chasing wires. Any advice from previous exp?
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Saturday, August 14th, 2010 AT 1:13 PM
Tiny
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Start with the light sockets. Make sure they are not worn and shorting. Follow the wiring back to the switch on the trans and check it for corrosion or damage.

Let me know what you find.

Joe
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Sunday, August 15th, 2010 AT 12:04 AM

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