Circuit/System Description

The head-up display is a secondary display system capable of reflecting important vehicle information onto the windshield. The vehicle information is displayed using virtual imaging and is reflected on the windshield in front of the driver. Battery positive voltage is the power source to the head-up display. The head-up display can only be enabled when the ignition is active and in RUN position. The head-up display receives vehicle information for display via the serial data circuit. The head-up display switch signal circuit is pulled up to battery voltage in the head-up display. The head-up display also provides the head-up display switch with a low reference. The head-up display switch is a momentary contact switch that connects a series of resistors in a resistor ladder format. The head-up display monitors the head-up display switch signal circuit to determine the head-up display switch inputs. Each switch state PAGE, UP, DOWN corresponds to a certain resistance value. The head-up display determines the switch pressed by the voltage drop across the resistors. The head-up display intensity can be changed by using the head-up display dimming switch. The head-up display is turned OFF using the dimming switch. The head-up display does not have a separate Off switch.