To replace the instrument panel accessory trim plate and the control assembly retaining screws, first take them off. Push down the control assembly retaining tabs to remove the control assembly from the instrument panel and remove the electrical connectors, pulling off the control assembly bulb that is stored for later use. For installation, reattach the control assembly bulb to the control assembly, reconnect electric connectors, make sure the control assembly is properly seated in the instrument panel with the retaining tabs and fix its position using the retaining screws and accessory trim plate. If the vehicle is provided with an Auxiliary Computer Climate Control System (ECC) and a rear overhead control assembly (without a sunroof) especially, after replacing the device main control system there has to be performed a special configuration procedure to fore ensure operation of the auxiliary control unit. In order to carry out this procedure, the use of scan tool would have to be installed, then the ignition is switched on and engine off, select Special Functions - Setup New HVAC, then Aux. HVAC (RPO C69). Press the Enter key and choose Programmed which is assigned with a star () next to Aux. HVAC (RPO C69) and press Save Options Softkey.