1996 Regal GS 3.8 cruise control not working & A/C sound

[RegalGS1996]

I have 106,000 miles on my baby (1996 Regal GS coupe) and want to work to keep her running for as long as I can. I use a private mechanic for most items but he doesn't work on A/C.

I just had the signal switch replaced (to fix brake lights that were not lighting) and had hoped that this would fix my cruise control - but it didn't.
What else to look at? Last year one day the cruise worked fine and then the next day not at all.

Also the A/C stopped blowing cool/cold air last year and I drove without it as I couldn't pay to have it looked at. I notice a differant pitch sound when the A/C is selected on climate control AND ALSO when I am running the defrost. Are these 2 related? Any ideas?

[BNaylor]

Best thing to do is get it scanned with a full function odb-ii scanner and see if any DTCs are stored in history. Certain DTCs will inhibit cruise control operation. Also, check any fuses that are related to cruise control.

What do mean by different pitch? The A/C compressor engages in the regular A/C modes and in defrost.