The head-up display (HUD) is a secondary display  system that optically projects critical vehicle information onto the windshield.           The head-up display (HUD) system has an electric tilt adjust that   is    controlled      by the HUD up/down switch. Moving this switch directs   the    motor   to move      the HUD image up or down on the windshield. The   HUD   is  also equipped     with    automatic dimming which gives the HUD   the ability    to sense outside   light     conditions,  via a photo-cell   and automatically    adjusts the brightness    levels.    You may  manually   adjust  the HUD image    brightness by moving  the   HUD dim   switch.
The HUD displays the following images:
|     •  | The speedometer reading (speed up to 120 MPH) | 
 
|     •  | The turn signal indicators | 
 
|     •  | The high beam indicator | 
 
|     •  | The check gages indicator | 
 
|     •  | The radio frequency, including AM, FM, CD, and Tape | 
 
|     •  | Values in English or metric units | 
 
Speedometer
The speedometer is shown on the HUD as a 3-digit display. The HUD speedometer  is capable of displaying up to 120 mph. The HUD receives a class 2 message  from the powertrain control module (PCM) indicating vehicle speed.  If the  class 2 message from the PCM is invalid the HUD will use a class 2  message  from the EBCM instead.
LH Turn Signal and RH Turn Signal Indicator Inputs
The left and right turn indicators are driven by hardware inputs from  the exterior lighting system. The signal is active when the circuit is high    (12 volts) and  inactive        when circuit is open. During hazard mode,    both the right and left  turn      signal   circuits are active high, causing    both the right and left turn      signal  indicators   to illuminate at  the   same time.
High Beam Indicator Input
The HUD receives a class 2 message from the BCM that the high beams  have been requested.
Low Fuel
The HUD receives a class 2 message from the IPC indicating low fuel.
CHECK GAGES  Inputs
The IPC monitors different inputs and vehicle messages and sends the  information to the HUD, via a class 2 message. The HUD illuminates    the CHECK GAGES indicator when it receives certain information from the  IPC.
The HUD will illuminate the Check Gages indicator for the following  messages:
|     •  | Charging system/generator fault | 
 
Radio
The HUD receives a class 2 message from the radio indicating radio frequency,  including AM, FM, CD, and Tape.
Backup Vehicle Speed
The HUD receives a class 2 message from the BCM indicating backup vehicle  speed.
HUD English/Metric Input
The HUD illuminates  the speedometer in either English (mph) or metric  (km/h) units depending upon the class 2 message received from the IPC.