The truck needs a tune up.
yes
Is it a 4 cylinder? Sometimes a 4 cylinder engine will shake a little extra when the AC is running and it's at an idle. You might be able to step up the idle a little extra but 4 cylinder engines are notorious for shaking when the AC is running.
Running the AC compressor uses horsepower, and the truck does not have enough to overcome the loss.
Might be a bad heater control
Yes, this is a normal operation for most newer cars, and is designed to help prevent windshield fogging when using the defrost function.
when running acand adling tuck vibration bad
Becuz running the air thru the AC system dries the air, otherwise it wud be blowing damp air onto your window resulting in fog or moisture on your window
It could just be the AC compressor causing the engine to shake when running at lower speed. If it's any more than that, the engine might need a tuneup, motor mounts or possibly a burned valve.
Look for the tube that takes the condensed water out of the cabin these sometimes get knocked loose by the feet of the passenger's
with the compressor running.
Start driving with your air conditioning on defrost, the AC will defog the windshield but you need to be moving.
Usually not.