Cadillac Repair: 91 Deville A/C compressor not coming on FF48, 134a freon, r 134a

Question
91 Cadillac Deville 4.9L 201,000 miles

I fill the A/C with freon R134a (retrofit), Both sides show 90psi. Compressor has kicked on once in a strange way. If comes on for 1 second 3 times in a row (on..off..on..off..on.off...doesn't come back on). I checked the codes per what you said on other questions and show code FF48 I believe (shows ..F next screen says F48). I cleared the codes and still would not come on, code came back after a while. jumped all switches on high side and on dryer canister and comp does not come on. Check fuses under hood and fuse under dash. I dont know how to jump the relay to make the compressor come on manually.

What does the code mean and what do you think the problem might be?

Answer
FF48 means that you have a very LOW amount of freon in the system. This code sets due to not enough freon in the system and or in most retro-fit systems from R-12 to r-134a freon is due to the sensor is NOT calibrated for the R-134a freon. try adding an additional 1/2 can of freon and then clear the code. I can provide you with PICTURES and test procedures and picture showing you how to jumper the AC relay to keep the compressor engaged so you can add additional freon. E-mail me at: onlineautohelp@msn.com and include your question and this answer as well as the YEAR-MAKE of car