So the truck is only blowing hot air. It does not appear that that compressor is coming on. I noticed that when I hit the A/C button the truck idles funny for a bit then goes back to normal. Is this a sign that my compressor is bad? Any help would be appreciated.

 

Before you buy a new compresser be sure to check the coil in the comp-clutch, that seams to be the first thing that goes bad, 2 wires and all you have to do is un plug it and check to see if there is any resistance, if no resistance the coil is bad, and they are cheap to buy, and simple to replace, dont even have to remove the compressor.
Let me know if you need one, I can tell you where to go.

 

it could be that the system has a leak.... If you know someone with a set of gages, hook them up and see...
A poorboy method is to check one of the schrader ports with a small screwdriver and see how much/if any freon blows out.

 

Whatever you do, do not burn up your clutch by testing it for extended period of time. If it gets hot, little metal fragments seem to come off the compressor wheel(?) and move down into the A/C tubes - thus clogging them and the in-line filter. Essentially, you'll have more parts to replace in your system than just the compressor (if the compressor is the problem).

I spent $1700 a couple of years ago to replace all the parts (installed).

 

The ac tubes are closed. Nothing can get into them. If that were true, the refrigerant would get out. 99.99% of the time, the gas has escaped your system, meaning there's a leak. Sometimes you can add more and it will be fine for a year, sometimes not. All depends on how big or small the leak is. Either way, there's a leak.