What year did GM switch the Bonny over to R134a ?

All or most cars were 1994. Yes you have R134a.

To add.. the nice thing about the change over was that they changed the standard fittings.

R12 fittings are different from 134a fittings and there is no way to confuse them when you try to hook up and recharge.

Awesome. Thanks guys. I was hoping it was R-134a.

My A/C has been freezing up. Hopefully it just needs some refrigerant. *crosses fingers*

Has anybody ever tried this stuff before? I just picked up a can tonight. Wondered if it was any better than traditional R134a...

Mind if I chime in here with a question?
My car obviously took R12, but someone has done some converting to R134A.
The lines appeared to have been changed, but now, one of the fittings (low pressure?) no longer connects properly to the condensor.
The line and condensor fittings differ in size. Is this because of the attempted conversion? How should I rectify: Change the condensor or change the line back, and just buy the R134A connection adaptor?

BTW, the o-ring fitting fits into the condensor, you just can't do the nut up.

Any advice is appreciated.

Thanks,
Adam