A/C Question/problem

My daughter has a 2014 Corolla. She was complaining at the end of last year the A/C would quit blowing cold while driving at random times. Once on a trip with her it quit randomly. I got out to look and observed one of the lines had frozen up, which to me indicates it was getting low on freon (could be wrong). Now, the A/C won’t turn on at all. I say that but it started working shortly last night while she and my wife were driving in it, but it quit not long after. I have put gauges on the car while it was not running and both sides are reading right at 100lbs, (low side dipped down to about 98), so pretty much balanced. When I turn the A/C on or off, I don’t hear the compressor cycle. Is it possible the freon level needs a boost to kick the pressure switch to allow the compressor to come on and the problem is just low freon/possible leak?

I’m not an AC mechanic, but 100 lbs static pressure seems too high unless the out door temperature is well over 100 degrees out.

Here’s a static pressure chart.


Ok, so going by the chart tester provided, with the temperature being about 86-88 that day, the gauges shown the levels were appropriate. That leaves me vexed as to why the lines were freezing up.

Check if the condenser is restricted with debris.


Ok, finally got her to stay home long enough to look at the car again. The condenser is clear. When i start the car, the fan does not engage. When I turn AC on, it does,which is telling me the circuit is completing. I don’t hear a definite “click” as the older AC units did because the clutch turns all the time so I have read, but I do hear something (possibly just the fan) turning on.

You are going to need a wiring diagram or a fuse/relay chart. If the fan isn’t kicking on, it could simply be the fan relay is bad. If the fan doesn’t come on, most AC’s that I have worked on will not turn on the compressor. If the fan relay is good, then the fan itself may have gone out, seen that too. It could also be the compressor clutch relay or even the compressor clutch coil.

Sorry, I guess you misunderstood. I was saying when I start the car with the AC turned off, the electric fan does not like normal since the car is cold. When I turn the AC switch to on, the fan kicks on like it should. If I understood correctly in something I skimmed over, there is something under the dash that controls the AC and not a relay under the hood as normal because the AC clutch always turns with the belt weather the system is on or off.

Make sure the vent system isn’t set to defrost mode.

Some vehicle HVAC systems automatically engage the compressor in that mode.


That is a variable displacement compressor, it doesn’t use a cycling clutch.
If the compressor will not build pressure, there may be a problem with the solenoid control valve inside the compressor.

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I did misread your post, sorry 'bout that. The relay is in the underhood relay/fuse panel. The only thing having any control of your AC under the dash is the expansion valve inside the evaporator, but I doubt that is the problem here.

When you say the clutch always turns with the belt, part of it always does. When the clutch engages, the center of the clutch starts to spin. When not engaged, the center is still while the pulley around it continues to spin.

If it is a variable displacement compressor, I don’t have any experience with them so I can’t help you with that.

Ok, been busy so just had a few minutes to look it over again. Put my gauges on it again, both level at 100-103 PSI. I got a test light and took it to my pressure sensor. I have 3 wires, red, blue, and black. I have power to the black wire. I poke the blue, nothing registers on the test light, but the motor idles different, like it is compensating for the compressor/under a load, when I remove the test light, it goes back to normal. Don’t really notice anything on the red wire. I did notice the high side line getting warm to the touch, which it hasn’t been, but still nothing on the low side, and the gauges remain unchanged during the entire process. Not sure if my switch or compressor is bad…never had this problem and I’ve fixed many AC problems before this new type of variable displacement compressors. Anyone have a final though before I bight the bullet and take it to a shop?

And then I find this…

AC amplifier. Never heard of it, but now there’s another possibility.

So just to give the thread the correct answer, I finally bit the bullet and bought a compressor. Changed it out, which was a lot easier than I thought it would be for a compact car with the compressor on the bottom, reccharged the system, and viola, cold air again.

It’s playing string music for you, in addition to providing cold air?