AC Staying On

I have a 1999 Silverado. I have noticed the AC stays on even if the light is off. Is this normal?

Are you talking about the compressor, or the blower motor?

This is true if you are in defrost or blend mode...by design.

I know it stays on anytime it's on defrost or floor/defrost. Is it also supposed to stay on when it's on floor/vent or just vent?

Mine blows cool air no matter what the AC switch is set to. I can also hear the compressor cycle on/off just like I had the AC set to on.

"Is it also supposed to stay on when it's on floor/vent or just vent"?
Fan yes compressor no.

I figured it out. I did not notice that it was set to recirc not fresh air. Once I set it to fresh air the AC stopped running. Apparently the compressor runs when set to recirc.