Cadillac Repair: old R12 A/C, cadillac fleetwood brougham, r 134 freon

Question
QUESTION: How to switch old R12 to R134 and about how much will it cost to replace system, should I have it done professionally or can I do myself? What do I need to get the A/C working again?

ANSWER: What YEAR is the vehicle ?.

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QUESTION: 92 Cadillac Fleetwood brougham 5.7

Answer
I get this question about 3 times a week. You CANNOT convert a 1992 Cadillac R-12 system to an R-134 system because the low pressure sensor is NOT calibrated for the R-134 freon. If you try, The check engine light will soon illuminate with a low pressure code and you will have to switch the complete system back to R-12.

As of this date, I have not heard of any FIX or replacement low pressure sensor to be able to convert the system.