AC has freon but the system cycles too fast and air doesn't get cold? on 1998 Mazda B3000

a local mechanic said possibly the switch, but I'm thinking power is on or off in a switch situation. Any ideas of yours would be greatly appreciated. It's my friends truck and I thought we should try more freon.

Asked by for the 1998 Mazda B3000
sounds like freon is low BUT it could be high or low switch issues also.also could be lazy clutch hub assm
thanks for your input. I'll look into that