A/C Issues (likely not evap core related)

[brimstn]

2015 EB
16988mi

Today is the third time I've had the A/C go out on me, all of them have been in rapid succession not having had any issues with the car until April 4 of this year.

1 - Diagnosis is lack of refrigerant. No dye anywhere in the vents or drain. Tech recharges system, cool again.

2 - 2mo later, no A/C again. Diagnosis is bad A/C clutch relay. Tech changes relay, cool again.

3 - Today, same issue. Doing my own diagnosis this time, the A/C clutch isn't engaging again. Swap the horn and fan relays, still nothing. Horn works with both relays. I'm thinking pressure switch(e)s at this point are preventing the clutch from engaging. I really don't have a way to check the pressures, but I do have a UV light and glasses...no dye anywhere around the schraeder valves, drains, or vents.

I'll be calling them tomorrow, just wanted to vent and/or get some input. Having it go out this many times with, possibly, three different issues in this short a timespan is maddening.

I am in the southeast (TN) so I am worried about the evap core issue, but I'm not seeing any dye anywhere and I'm only at ~17k mi (even tho there has been reports of them failing earlier than 25-30k).

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[notstok5.0]

a/c clutch won't engage if you don't have refrigerant (my understanding at least). Also, the evap is sealed so they won't see it leaking there. This sounds like a leaking evap core to me. Did they run an overnight pressure test on the system?

 

[brimstn]

a/c clutch won't engage if you don't have refrigerant (my understanding at least). Also, the evap is sealed so they won't see it leaking there. This sounds like a leaking evap core to me. Did they run an overnight pressure test on the system?

Yah, that's why I'm thinking there's no refrigerant...pressure switches preventing the compressor from kicking on.

Both times they've had it it's only been for a few hours despite me complaining about the evap issue, which they claim they don't know about. The evap isn't 'sealed' per se, it's open to the vents and the condensation drain...if it was the evap one would expect to see dye (injected during the first trip) in and around the drain and vents...nothing there.

I'll report back once I get it in to the dealer and at least documented in the system.

 

[Louieg58]

I am having very similar issues on my 2016. My AC compressor clutch won't engage today and is just blowing warm air. This is the 3rd time I've has issues with the ac. First time they replaced the compressor and second time it was a leak in the low pressure line. I've asked about the evaporator core each time but they said it has not been the issue. Each issue has been pretty consistent once a year. Pretty frustrating especially as it starts to get warmer.

 

[Deleted member 35786]

Yah, that's why I'm thinking there's no refrigerant...pressure switches preventing the compressor from kicking on.

Both times they've had it it's only been for a few hours despite me complaining about the evap issue, which they claim they don't know about. The evap isn't 'sealed' per se, it's open to the vents and the condensation drain...if it was the evap one would expect to see dye (injected during the first trip) in and around the drain and vents...nothing there.

I'll report back once I get it in to the dealer and at least documented in the system.

Print the Evap Core TSB and take it with you.
https://ford.oemdtc.com/3936/poor-air-conditioning-a-c-performance-2015-2017-ford-mustang#more-3936

 

[Cobra Jet]

Here’s how you can tell if it’s the pressure switch (IF A/C system has already been determined to be full of refrigerant):

1) Pop hood and locate A/C pressure switch.
2) Unplug the harness from the switch.
3) Get a paper clip (or piece of wire w/stripped ends), bend the paper clip or wire into a “U”.
4) Jumper the harness plug contacts with the paper clip (or wire).
5) Start car; turn on your A/C.

Does the clutch engage and compressor kicks on?

If yes - it’s the pressure switch.

 

[Deleted member 35786]

Any update?

 

[Cobra Jet]

This SSM was just released a few days ago. I’m not sure if this is applicable to the S550 unless someone can confirm the S550 has a EVDC A/C compressor:

 

[Deleted member 35786]

This SSM was just released a few days ago. I’m not sure if this is applicable to the S550 unless someone can confirm the S550 has a EVDC A/C compressor:

Very interesting! Seems most of these so called compressor fails are really the clutches burning up.

 

[autobahnGT350]

Well, going back to the shop for the third time in three years for defective AC. Stopped blowing cold air. This sucks, maybe this bulletin will help. Thanks for posting.

 

[Cathul]

I know it's a month since last post, but the GT doesn't have an EVDC compressor. This is only for the Ecoboost.
Start the car and check if the clutch engages or not. If you have enough refrigerant and don't have any error conditions stored related to the pressure sensor then it might be that the shaft seal on the compressor is leaking oil preventing the clutch from engaging even if it gets the 12volt to engage (you can actually measure this on the clutch connector).
If this is the case you need to replace the compressor again.

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