2003 Ford Truck Ranger 2WD
2.3L MFI DOHC

I am puzzled: About a month and a half ago, as soon as it started getting warmer the AC started working on and off, it seemed as it would only work in the cooler mornings.
-First thing I tried was the simplest, adding more R-134A. That didn't help. It actually quit working on cooler mornings after that.
-A guy at work suggested maybe there was too much pressure, so he pulled a vacuum of the system, and added more refrigerant, but that didn't help.
-He then told me that if the clutch coil had current, and it was not engaging, it was probably a bad clutch, so I went and bought a brand new clutch and installed it, but that didn't help either.
-Then I replaced the relays, and one night (when it was a little cooler) I jumpered the relay (with a paper clip) and the clutch engaged and the AC started working great. I was relieved that the compressor works. I put the relay back on, and drove and after a few minutes the AC shut off.
-The next day, I tried it and it didn't work. Not even jumping the relay.
-This morning, I started the truck, and the AC ran for about a minute, and then stopped.
I believe there is enough refrigerant, and the low pressure reads good.

Could it be a faulty pressure switch? Do the pressure switches work BEFORE the relay? of after?

When I unplug either of the switches I can hear the change in the truck's running, so I assume this means they work, but I am going crazy trying to figure this out.
Anything else I should look for?

Thanks in advance!