Monitor Check

Monitor Check

Overview of display unit

- The display unit communicates with the navigation unit over its own GA-Net bus. Information is sent to the navigation unit whenever the user activates the touch screen, or hard buttons. Information sent by the navigation unit to the display unit includes commands to control the LCD back light.
- The display unit is protected by the security system by daisy-chaining the security signal through it, and then passing the signal to the audio unit.
- The illumination input from the gauge brightness control provides back lighting for the hard buttons surrounding the screen.
- The display unit also communicates with the climate control module to set the A/C mode, and fan speed, and to receive the outside temperature that is displayed on the A/C-INFO screen.

These screens allow troubleshooting of the display unit. Touch the menu item you want to troubleshoot, and follow the diagnostic instructions.




RGB Color

This screen verifies that the display unit is receiving the video (R, G, B and Composite sync) signals properly. The three primary colors should all be shown without distortion. The combination of all three should produce a central white section. If any of the colors are missing, troubleshoot for the color signal. If the picture has lines in it, or scrolls horizontally or vertically, troubleshoot for a Composite sync problem.




Gray Tone

This screen diagnoses problems with contrast. You should be able to see the changes from bar to bar across the scale. It is normal for the 2 bars on either side to appear the same.




White Raster

The entire display must be shown in white.




Black Raster

The entire display must be shown in black.



Test Pattern

The chart below; shows the colors being used for the map and menu screens. This is for factory use only. To check the color signal use the "RGB Color" diagnostic.




Monitor Adjustment

This allows the navigation display to be centered. Use the joystick to move the picture up/down or left/right. It is unlikely that you will ever need to adjust the monitor position. The "Default" button will reset the display position to factory specifications.




Touch Panel Check

The panel touch sensing system consists of a touch sensitive resistive membrane covering the display. Contrary to other systems using infrared beams, the screen has to be physically "touched" to make it work. The display has capability of an almost infinite number of touch locations. However, to be compatible with earlier systems, the software only senses the locations shown on the diagnostic screen above. Every possible touch button position is shown on this diagnostic screen. Touching one of these areas should cause its color to reverse, and sound a "beep". If the touch locations are off slightly (by less than one touch locations), use the "Touch Panel Calibration" diagnostic to re-align the touch "zones" with the screen image. If any areas of the screen either don't respond, or respond at some other location when touched, then replace the display unit.

NOTE: Unlike earlier screens that used infrared sensors, direct sunlight will not affect this test.




Touch Panel Calibration

The display screen uses a touch sensitive membrane instead of fixed infrared "beams". This means that every location of the entire surface of the display is touch sensitive.

For the display to be compatible with earlier navi systems, the system software creates "touch zones" emulating the touch "switches" created by the intersections of 20 vertical and 9 horizontal infrared beams. This diagnostic allows alignment of these artificially created "zones" with the location of the buttons images on the screen.

Normally this should never need adjustment, and it used only to adjust the touch locations for parallax (the touch locations appear different when viewed at an angle). However if an adjustment is necessary, the procedure is as follows:

- The screen consists of four test areas consisting of a "+" button and an adjacent box with a black border. Touch the four"+" buttons to verify alignment. If when you touch a "+" button, the adjacent box becomes yellow, then perform the following. Continue to hold the "+" button, and simultaneously move the joystick to shift the screen slightly from side to side or up and down. The adjustment is complete when you can touch all four"+" boxes and not see any of the adjacent boxes become yellow.
- To store any changes you make, push in the joystick.
- To reset the touch zones to the factory default touch the MAP/GUIDE button.
- Use Return to exit the diagnostic.