To replace an AC valve, detach air conditioning lines, pry out the glove box, remove the bold, pry off the airbag, open the evaporator to access the valve, and replace the valve with a new one. You need a replacement air conditioner valve and various wrenches to complete the process.
Unhitch the air conditioning lines, and unscrew and remove the glove box from the plastic latch to uncover the evaporator. After removing the bold, free the water drain tube that sits near it. Then, disconnect the car battery, unfasten the bolts that hold the airbag in place, and remove the airbag.
Pry out the Styrofoam casing to expose the evaporator, unscrew and unclip the evaporator, and open it. Ensure that you clean off the evaporator if it is dirty. Then, pry out the valve, and set it aside. Put lubricant on the o-ring of the replacement valve, and install the new valve.
Next, put the rubber seal on the engine bay, make tight the seal, and use the correct wrench and bolts to reinstall the evaporator. After closing the evaporator, cover it with Styrofoam casing. Reinstall the airbag, plug in the battery, tighten the water drain tube and put the bold back in place. Secure and hook the glove box. Lastly, hook back the air conditioning lines.