2011 mustang gt ac problem
 

ok folks, we have a 2011 mustang gt with manual air conditioning. the problem is the ac is erratic, it may stop cooling going down the road cruising or won't start up when you first start the car. it has a full charge of freon. it has so many sensors don't know where to start trouble shooting. has any one had a similar problem and what was the diagnosis. I can't afford a big troubleshooting bill, need to fix this my self. forgot to say blower motor is running the whole time just the compressor isn't coming on

I'm currently conquering A/C problems with my 2010 mustang. Is the compressor not coming on? or is the clutch not engaging. My Clutch wasn't engaging. In the summer of 2017 I took it to a shop so they could put in a new EGR valve and do an A/C check cause it was starting to have issues were it would work and then not. They drained it, refilled it and put in a dye and couldn't find anything wrong. Well needless to say the A/C just stopped working and I figured it might be a big issue and wallet drain so I lived without it (in Texas ugh). This summer started to kick in and I figured I should tackle it. Here's what I have done so far.

First I changed out any fuses and relays. These were not the issue. I started to think it might be the A/C compressor switch. But I wanted to check one relay again (A/C clutch relay) and wanted to jump it with a wire or paperclip to see if the clutch would engage. Just to make sure I had a friend help me yesterday. He put a wire in the pins for the A/C clutch relay but it didn't do the trick. I told him we should check the refrigerant level cause the guy at AZ said it was high. It was sitting at 110 in the red zone. we released some of the pressure got it back into the green zone and the clutch engaged! but it wasn't blowing cold, so he added more refrigerant which took us back into the red zone again but not as high and it works fine now. However my system seems to be pulling really hard and fluctuating a bit more than it should. He believes the A/C receiver dryer #4 in attached diagram is failing and needs to be replaced. I've found the part as cheap as $10. Now its a matter of locating the location, but I believe its on the side of the condenser.

In short if your clutch isn't engaging, check all your fuses & relays, refrigerant pressure too low or high won't let the system work, a/c compressor switch (possibly #27 in diagram), and a/c receiver drier. Diagram however is for a 2010 Mustang, yours may or may not be the same. Hope this helps.
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