switch, relay or blower motor problem as a guess.
you have to turn them not push them
you need to repleace the blower motor resistor under the das on the passenger side
Press the little button by the left hand tuning knob of the radio
Had same probllem on High. 2002 "The fan blows cannot control temperature via temperature knob on the dash?" Knob was useless. Turns out that the problem was the A/C/Heating control unit. Replaced under warranty $1000
Oven control regulator
the left knob controls hot water.
To set the temperature on an air conditioner, locate the thermostat or control panel, which may be digital or have manual dials. If it's digital, press the temperature up or down buttons to adjust to your desired setting. For manual dials, turn the knob to the desired temperature. After adjusting, wait a few moments for the air conditioner to respond and reach the new setting.
The knob that adjusts the driver side mirror also adjusts the passenger side mirror. Simply turn the knob to the right to adjust the passenger side, and turn to the left to adjust the driver side. Leaving the knob in the middle, neutral position will keep the mirrors from changing if the knob is hit.
Neither one will make any difference in water pressure.
There is a torx screw on the same side as the button, unscrew it half way and lift up the shift with the boot.
It is best for the vehicle if you are at a complete stop, put the trailblazer in neutrail, turn the selection knob to your right to whichever setting you would like, wait for it to engage, then put it in drive and take off!
== == try charging your air conditioner, maybe chek the lines fo leaks