A/c my 92 serria has had an a/c problem for a few weeks, fistly the a/c icon on heater controles will blink then stop when i start the truck. then if i try ti use the a/c it will do the same thing.the a/c compresser will not enguage and it sees to be blowing hot air.i have tried to top up my referigerant , no change.dose anyone have an idea?

Is the A/C 134A or R12? There is safety switch in your canister on the passengers side, if it is below the safe level, it will not engage the compressor clutch. Make sure your refill charge is the proper brand, either 134A or R12. One sure way to check if your level is low, remove the connector wire to the canister and place a jump wire across to two, if the compressor clutch engages, your level IS low.