Power and Ground
The HUD will operate properly over the 9 to 16 volt range. The HUD module receives battery positive voltage from the underhood fuse block. The HUD module receives ignition positive voltage (IGN3) from the rear fuse block. The HUD module ground is located at G201.
HUD Image Automatic Brightness Control
The HUD display intensity is controlled by two parameters according to an automatic brightness control (ABC) dimming signal. These two parameters are the dimming potentiometer input, and an on-board photocell.
HUD Image Intensity Control
A dimming switch is used in order to allow the driver to manually adjust the brightness of the HUD display. The dimming switch provides an input to the HUD. The input is pulled down to ground within the HUD. The dimming switch has an OFF detent where the dimming signal is shorted to ground.
HUD Image Position Switch
The HUD image position switch provides two inputs to the HUD. These two inputs control the motor. The motor controls the height adjustment of the HUD. The switch is a rocker type switch with both sides of the switch being switches between ground and battery. The nominal position for both sides is switched to ground. Whichever switch becomes switched to battery determines the rotation of the motor.
HUD Speedometer
The HUD control module receives the vehicle speed signal (VSS) from the powertrain control module (PCM), via a discrete circuit. When the HUD control module detects a VSS input the respective vehicle speed is displayed.
HUD English/Metric Input
The HUD can display the speedometer in either English (mph) or metric (km/h) units depending upon the class 2 message received from the IPC.
LH Turn Signal, RH Turn Signal, and High Beam Indicator Inputs
The left and right turn indicators are driven, via a discrete circuit from the exterior lighting system. The signal is active 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.
The DIM monitors the high beam switch input and sends the switch information to the HUD, via the class 2 serial data line.
CHECK GAUGES Inputs
The IPC monitors different inputs and vehicle messages and sends the information to the HUD, via the class 2 serial data line. When the HUD receives the information, the Check Gauges indicator illuminates.
The HUD control module also monitors some class 2 messages and will illuminate the Check Gauges indicator for the following messages:
| • | Engine Oil Low Pressure |
| • | Air Bag |
