Have you performed the Climate Control Unit's self diagnostic test?
It's on page 22-12 and 22-13 of the service manual found on this site in the Wiki.
This is a good place to start if you want to diagnose your vehicle's a/c problem.
This section of the manual has some other tests and flow sheets that will also help you to narrow down the possibilities.
If you properly diagnose your car's problem you won't be replacing parts you don't need and you won't repair that which is not broken.