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 the 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 below. Every possible touch button position is shown on this diagnostic screen. Touching one of these areas should cause its color to reverse, and the sound a "beep". If the touch locations are off slightly (by less than one touch location), use the "Touch Panel Calibration" diagnosis 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 navigation display.