Auto Air Conditioning & Heater Repair: air conditioner does not work at idle, chevy ck, freon

Question
i have a 88 chevy ck 1500 with a v8 engine..
my air conditioning system was replaced last year. when i am accelerating the ac works fine. also when i am on the highway the ac works fine.
the new air conditioning system was converted to 134 from r12.. the compressor occasionaly will produce cool air if i am parked in the shade.
but for the most part it will blow only hot air while idiling.. i have looked under the hood at idle and the compressor isnt engaged.. im at a loss..
is the some sort of adjusment somewhere to correct this problem ?
please give as much feedback as possible..

Answer
Your problem appears to be that the system is LOW on FREON most likely due to a leak somewhere in the system.

Try adding ONE can and ONE can ONLY of freon and see IF your compressor engages at idle and your system goes back to normal. If it does, You need to fix the leak or forever be adding freon.