AC issues, anybody got a guess?

[sms2022]

Before the car goes to the dealer and I have to rip out all the flex fuel sensor plumbing I just put in, anybody have a guess what might be causing this:

AC blows hot. Forscan shows good pressurization so not an EVAP leak. No faults detected and ran PCM self test with no issue. Blows hotter on Auto mode than if you manually switch on AC.

If not then I’ll be returning the car back to stock tonight for its trip to the dealer tomorrow morning. Bummer. Supposed to be nice this week too.

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[ORRadtech]

Can you verify the compressor clutch is kicking on?
I'd personally want to see manifold guages hooked up to get an accurate reading.
But if you just want a top-of-the-head WAG I'd say blend doors.
Not sure why you think you need to go back to stock for an AC issue though...

 

[Cobra Jet]

Could be bad A/C pressure switch, if the switch is bad the compressor won’t kick on. Are you able to tell if the compressor is kicking on or not? You should be able to remove the connector plug from the switch, jumper it and the compressor should kick on.

Can you hear the blend doors opening/closing?

Another common S550 A/C issue is the compressor coil failing too. I do not know if this thread will help, but here’s some info on that:
https://www.mustang6g.com/forums/th...tch-and-coil-replacement.141934/#post-2908198

 

[sms2022]

Can you verify the compressor clutch is kicking on?
I'd personally want to see manifold guages hooked up to get an accurate reading.
But if you just want a top-of-the-head WAG I'd say blend doors.
Not sure why you think you need to go back to stock for an AC issue though...

Dealer is obnoxious about mods. Just don’t want to chance it. They were quizzing me down about my steeda shifter bracket and what other mods I had the last time I was there for an oil change.

 

[sms2022]

I’ll test the switch tonight. Anything more involved it’s just gonna have to go in

 

[cmxPPL219]

Before the car goes to the dealer and I have to rip out all the flex fuel sensor plumbing I just put in, anybody have a guess what might be causing this:

AC blows hot. Forscan shows good pressurization so not an EVAP leak. No faults detected and ran PCM self test with no issue. Blows hotter on Auto mode than if you manually switch on AC.

If not then I’ll be returning the car back to stock tonight for its trip to the dealer tomorrow morning. Bummer. Supposed to be nice this week too.

OP - Per Dave, can you hear the compressor cycling on and off?
If not, and if you've verified no leaks and good pressure, it could be ambient temps. What was the temp in Detroit (I see that's where you are)?

If it's too cold outside, compressor will not kick on. What have the temps been lately and on the days you tried turning it on? Anything right around freezing and slightly above, it won't come on due to the pressure differential.

If you can somehow try turning on A/C in a heated or warmer garage/underground parking, etc.?

 

[sms2022]

OP - Per Dave, can you hear the compressor cycling on and off?
If not, and if you've verified no leaks and good pressure, it could be ambient temps. What was the temp in Detroit (I see that's where you are)?

If it's too cold outside, compressor will not kick on. What have the temps been lately and on the days you tried turning it on? Anything right around freezing and slightly above, it won't come on due to the pressure differential.

If you can somehow try turning on A/C in a heated or warmer garage/underground parking, etc.?

Hmm that’s a good thought. However, it was about 65 degrees yesterday when it wouldn’t kick on. Ill have to listen closer, the rpm’s go up like the compressor kicks on but I don’t hear it actually cycling.

 

[Torched10]

Hmm that’s a good thought. However, it was about 65 degrees yesterday when it wouldn’t kick on. Ill have to listen closer, the rpm’s go up like the compressor kicks on but I don’t hear it actually cycling.

If you turm on window defroster it turns on ac regardless of ambient

 

[furdfan2018]

Ford has a history of bad AC compressors. Just because the system is charged doesn't necessarily mean the compressor is functioning properly.


https://www.mustang6g.com/forums/threads/ac-compressor.161400/

https://www.mustang6g.com/forums/threads/a-c-compressor-not-spinning.175342/

 

[Scuba]

When I got cams installed on my S197, the AC didn't work when I picked it up. The shop swore they didn't do anything to the AC system. Wasn't a big deal, I hardly ever turned it on anyway.

After a month or so, I was digging around under the hood and found a connector wasn't plugged in. Didn't even know what it was at the time, but when I plugged it in, the AC worked

 

[Garfy]

Hmm that’s a good thought. However, it was about 65 degrees yesterday when it wouldn’t kick on. Ill have to listen closer, the rpm’s go up like the compressor kicks on but I don’t hear it actually cycling.

Instead of "listening" or watching the tach, why not open your hood and visually look at the compressor to see if the clutch is engaged and turning the compressor? That's the best way to see if it's actually turning.

 

[Nickel]

Last year on my 16 GTPP, the car suddenly started to blow hot air. I took it to my wife's dealership, and my friend found that one of the schrader valves was loose. Tightened it up, recharged and she was good to go.

 

[sms2022]

Just heard back from the dealer, it was a chafed wire on the harness going to the compressor. Like I posted about in my active exhaust thread that’s what happens when you don’t wrap the last 6 inches of wire near each connector. Built ford tough lol

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