If i turn on the AC when the clutch engages the truck wants to stall and the clutch does not spin at all

anyone know what could be the cause?

Video below

 

It's hard to tell from the video. Is the outer pulley part under the belt stopping? Or is it turning free?

If the pulley is completely stopping when the clutch engages, or if the pulley slows down, and the clutch starts heating up, then the compressor is seized and your clutch is trying to stop the engine.

If the outer pulley at the clutch doesn't change speed, but there is a big "click" and some visible movement at the compressor clutch, then the clutch itself is shot (possibly because of other issues, like a seized compressor).

If there is no movement or clicking sound at the compressor clutch, then the system has lost charge and there's no pressure. There's a safety switch in the system which will prevent the compressor clutch from engaging if there is insufficient refrigerant pressure. If that's what you have, you're looking for a leak first, and after fixing the leak, recharging the system.

One more thing, with the engine off, you should be able to grab the clutch center and turn the shaft of the compressor by hand. If you can't, there's something seized in the compressor.