I am a novice on auto air systems, but this is what I know.

I checked the gas, and the pressure is fine. So I assume the compressor is working, and the system is not low on gas.

When I get to freeway speeds, it puts out cool air but not very much.

You can hear the compressor cycling on and off very quickly. Something like 5 seconds on, then 5 seconds off. So I am wondering if it is a high pressure switch.

Is this something I can fix myself? I am laid off, so I can not afford taking it to someone, so I am hoping I can buy the hihg pressure switch (if that is what it is) and replace it myself.

Thanks for any help.

-Bob

First thing I would recommend is that you do take it in and have the system charge checked. Low charge is often responsible for short cycling.
Unless the problem is actually a switch. The only problem here is: you don't know which switch. The Low pressure switch and the High pressure switch are in series. Not likely your problem.
If you do take it in, they should inspect for leaks in your system and check to see why the condenser fan isn't working (cooling the a/c only while you are moving), which could be as simple as a worn or corroded condenser fan relay...

-----OR-----

... the charge could be so low that the Power Control Module (PCM) isn't commanding the fan on.

The basic air conditioning troubleshooting steps below should help:

https://www.askmehelpdesk.com/cars-t...ml#post1864159