My 97 Bonneville SE went through an engine rebuild roughly 3.5 years ago, and the A/C has been inconsistent ever since. But the past year or so has been the worst. The fan rarely comes on, and when it does, the air flow isn't full strength and is either barely cool or hot (even though it says the a/c is on). Just charged it with freon, and the mode valves work. The A/C clutch on the drive belt is engaging and the fuses are all in order.

I'm out of ideas. My last guess is a wiring problem of some kind?
Any help at all would be appreciated.