2000 Chevrolet Monte Carlo hvac

check the ground and the actuator for temp control it may be sticking. ground is behind left side of dash by brake pedal bracket. the actuators are vacuum controlled so it may be loose or the vacuum motor sticks.

Replaced actuator and it still isn't working properly. It kicks on sometimes when I hit the dash on the passenger side

then you'll have to check for a vacuum leak or a pinched line. if you are hitting it , it has to be jarring something to make it work it cold also be the control head as well. when you say it works does the blower work as soon as you turn it on or after you hit the dash? if it's that where the blower works after you hit the dash then it's either a bad ground for blower, or the module, see pic. you might see if the power comes to it whenyou turn it on then goes out if not maybe you can change a like relay and see if that fixes it.