2012 Honda Civic AC question

Tonight is 62F no sun no heat only 46F, should be 40to 42F, what causing or what controls the compressor I think is going off?

Without knowing what the pressures on both low and high sides at idle and at elevated RPMs there is no way of knowing what the real problem is.
There should not be any “think” involved as to whether or not the compressor is engaging. Working properly, there should be no problem with at least 40 degree F vent temps even on a 100 degree day.

Fifty two while moving is not good and it drops from 62 at idle simply because the compressor is turning faster.

What are you saying don’t make any sense, because with 100F you never ever get 40F on very good compressor will be 50F natural pressure is going up, I asked what control compressor going on and off???

I expect that is controlled by a sensor which measures the air temperature inside the passenger compartment.

I made plenty of sense and if an A/C only puts out 50 degree air on a summer day when it hits 100 then it’s going to be uncomfortable inside the car.

It gets plenty hot here in OK (113 is the record in my area) and 35 or 40 degree outlet air is quite common even on 100+ days. The high humidity and high dew points make it even worse; much worse.

I have no idea what your compressor is doing as you have not made one mention of static pressures, low and high pressures at idle and elevated RPMs and so on. My assumption is that you are using one of those DIY recharge kits and those tell you nothing.

I guess the idea that this vehicle needs a good AC shop to fix it is not going to surface.


Good pressure should be from 28 to 32.

The low side pressure is fine. The big unknown is what is the high side pressure.

Having 32 on the low side means nothing if the high side is 120. How cold it gets depends upon the pressure drop and that is dependent upon the expansion valve or orifice tubes on cars equipped with the latter. High side needs to be over 200 at idle.

A note here involving safety. If you decide to use a set of manifold gauges and have an open can of refrigerant tapped NEVER under any circumstances open the valve on the gauge’s high side. That would apply high pressure to the can and likely lead to a can explosion. Other than scaring one to death it can also be very dangerous. A second or two of refrigerant into the eyes can lead to your being blind. Forever.

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That good my body has manifold gauges I ask to borrow. If high side will below 200 ,what that mine, what a problem? or will be high mine good.

Post back with pressures once you connect a gauge set. Note the static pressure when you connect the gauges. Static pressure means with the engine NOT running. Both low and high side pressures on the gauge set should be in the 120 PSI range. If it’s 100 or less for example then the system is undercharged.

With engine running and A/C on note low/high pressures at idle and at elevated RPMs; say about 2000. Knowing pressures would provide a lot more insight into this.

Since you insist on continuing here even though you really don’t know what you’re doing, at least make certain that you’re wearing good safety glasses to try to protect your eyes if something goes wrong.


Excellent point. One can lose their eyesight permanently in just a second or two if there is a refrigerant discharge for whatever reason.

Gloves are a beneficial necessity also. Frostbite can occur in seconds. It happened to me when I got a bit careless with a home central unit. The tip of my right forefinger is still numb to this day.

I could tell you about the time my “repairs” caused my refrigerator to catch on fire … lol …

Another story we need to hear George
?. :laughing:

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Agreed!! (10 character limit…)

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High side is 150

Sounds like it’s undercharged.

I might ask if the system was completely empty of refrigerant and if so was a vacuum pulled on it before any recharging?

What is the static pressure (engine and A/C off) on both low and high sides after it stabilizes; meaning sits inert for at least a few hours? Should be about 120 or so. The 150 you have now is not much above what should be normal static pressure.

My 40 year old fridge started acting up. I discovered the evaporator was totally frozen, solid ice. Thought the problem might be the defrost timer. hmmmm … I’m thinking … I wonder what a defrost timer looks like. The repair instructions say it is located near the compressor, so I find something that might be a defrost timer located there, relay-like gadget, so I remove it. Uncertain what to do next , I phone up my local appliance repair parts guy who tells me what I removed is not the defrost timer… It’s the compressor relay. He seemed a little concerned I had removed it. Then he explains how I can tell if the problem is the defrost timer, but first I’ll need to replace the compressor relay.

I noticed when I removed that part it appeared slightly melted, and the connections charred. Not wanting to sweat the details, I installed it back where it went and plugged the fridge in. Ooops… big problem. Smoke and fire at the compressor relay. Apparently that relay was on the verge of a breakdown; just removing and replacing it was the final straw.

And that’s how my fridge caught on fire.