I have a 2009 silverado. The ac on high blows very weak to the point where it gets hot. It's intermittent though sometimes it'll blow high. I can hear a slight wiping sound from under pass dash. I'm not sure if it's a control unit issue or what. Any help from a more technical person would be greatly appreciated

Sounds like a Blower Motor Resistor.

But to kick on and off? What about the havac control? Where ac sped is adjusted from?

You didn't state it kicks on and off, only that it was weak at high speed. and some times blows hot.

You should take somewhere that they can look the system over.

It could be low on freon.

It could also have a bad blend door motor causing it to blow hot instead of cool air.

If the Blower motor speed is affected, I would suspect the Blower Motor Resistor. Mine started to intermittently die at high speed. Eventually it would no longer work on high.

Sorry I was nt clear it never completely stops blowing it's just the intensity is next to nothing very low but still cold

how hard is it to gain access to the resistor? will dash need to be removed?

Could be a programming issue with the control head inknow theres a bulletin on losing ac

No, There is usually a cover down below. If its like the GMT800 trucks it's 3-4 bolts and the cover comes off.

So from what it sounds like is its 1 of 3 things the blend door actuator the ac control switch panel or programming of ac control panel

sounds like a blower motor.