Head Up Display (HUD) - System Operation and Component Description: HUD

Brightness Controls 

The HUD display illumination is controlled by two sets of inputs: the base HUD background and driver selectable illumination level. The base HUD background display uses ambient lighting of the road ahead of the vehicle and an overall vehicle backlighting dimming level to determine the display illumination level. The driver then has the ability to select a desired illumination level, which is selectable through the HUD menu. When a forward collision warning event is in progress, the illumination intensity is increased to provide an increased level of severity to the visual warning.

The HUD module uses the following inputs to control the illumination brightness:

• internal combiner HUD ambient light sensor value
• HUD brightness menu

The HUD uses an internal ambient light sensor to determine the illumination level of the display. The end-point of the light guide is forward-facing. The light sensor can be cleaned with caution, but cannot be repaired or replaced separately from the HUD.

Once the HUD has established a base illumination level, the driver can then select a desired illumination level. When the driver has selected to change the intensity level, the IPC sends the HUD brightness menu message to the HUD module over the HS-CAN3 to open the brightness menu. The driver can then change the intensity level using the menu options.

Display Adjustments 

The HUD provides adjustment settings to allow the driver to adjust the vertical position and size of the display to provide better viewing. The adjustments allow for vertical position adjustment of the blue display frame and vertical size adjustment through the HUD menu.

The HUD module receives the HUD settings active and HUD adjustment menu request messages from the IPC over the HS-CAN3.

The HUD module receives the steering wheel message center and HUD switch data message from the GWM over the HS-CAN3.

The GWM receives the steering wheel message center and HUD switch data message from the SCCM over the HS-CAN2.

Display Controls 

The HUD display controls are through the RH steering wheel switch. The HUD module receives all switch control inputs from the GWM over the HS-CAN3. The GWM receives the steering wheel message center and HUD switch data message from the SCCM over the HS-CAN2.

Engineering Test Mode 

To enter the HUD engineering test mode, begin with the ignition OFF. Press and hold the RH steering wheel switch OK button. Place the ignition ON and continue to hold the button for approximately 10 seconds until the HUD displays ETM in the upper LH corner of HUD image. Release the OK button within 5 seconds of ETM being displayed. Press the up or down arrow buttons to navigate through each of the display windows. To exit the HUD engineering test mode, place the ignition in OFF.

English/Metric, Language And Unit Selections 

The HUD English/metric, language and unit selections are controlled by messages sent from IPC. The IPC is the controlling module for the English/metric, language and unit selections and is based on the driver selections. The IPC and the HUD English/metric, language and unit selections are displayed the same.

The HUD module receives the language selection and trip unit selection from the IPC over the HS-CAN3.