Can I believe my mechanic

["Anzalone, Louis" <lanzalon@ecri.org>]

Had week A/C and took my 1990 200Q to the mechanic. 
He said he would charge and put a dye in to trace any potential leak.

When I picked up the car the A/C was real good for about 15 minutes then is
stopped working all together.

Took it back and he said no power was getting to the compressor. After
having the car for two days he said he ran onboard diagnostics which
indicate I need either a Programmer or a Control Head.

Coincidence after the charging?

Do I need to replace these major components on a trial and error basis?

Where should I source parts? - Used?  New? Rebuilt?



Thanks in advance for your help.

Lou Anzalone
1990 200Q