02 Frontier A/C help

[zx6r-kid]

I just bought this Frontier and the A/C button seems to come on when it wants to, not when you push the button. Pushing the button doesn't engage the compressor. Higher revs don't help. It you just leave it on while driving it will eventually kick in.On another note (possibly related), the dial switch from vent to defrost does nothing. No matter where you turn the dial the air comes out of the top vents (in your face) only.

Thanks for your help.William02 Frontier Ext Cab KA24DE