Begin with taking off the instrument panel's center stack bezel and then take out the center
Air Duct to work on the control assembly. After that, unscrew and remove the heater-A/C control head, then take off the cable. Connect the cable from the control head to the car's main computer, install the A/C/heater control head in the dash, put the center air duct back in place and at last, put the instrument panel center stack bezel back where it belongs.