HVAC Bulb Illumination

The scan tool displays 0-100%. The illumination percentage varies based upon the dimming switch information sent by the IPC on the serial data line. When the dimming switch is rotated to bright, the HVAC illumination percentage will increase. When the dimming switch is rotated to dim, HVAC illumination percentage will decrease. The headlamps or parklamps must be ON to read HVAC illumination data.