Summary

Figure 13-34. GM night vision HUD system schematic. (GM Service and Parts Operations)

Instruments include gauges and warning lamps. There are various types of gauges, including mechanical, bimetallic, electromagnetic, and electronic. Avoltage drop, a grounding switch, a ground sensor, or fiber optics can light warning lamps. Late-model vehicles may have a digital display instead of traditional analog gauges. Digital displays can be individual or they can be part of a more elaborate vehicle electronic system, such as a trip computer or message center. Electronic instruments or driver information systems (DISs) have the same purpose as the traditional analog instruments: The DIS displays vehicle-operating information to the driver and includes all gauge and speedometer information. The primary difference between the electronic (DIS) and traditional systems is the way in which the information is displayed. The DIS is also called a driver information center (DIC). Body control module (BCM) computers act as managers of other computers in a comprehensive vehicle system.

Electronic displays may use a light-emitting diode (LED), a liquid-crystal display (LCD), a vacuum fluorescent display (VFD), or a cathoderay tube (CRT) to transmit information. Some instrumentation is menu-driven, giving the user an opportunity to select the information to be displayed. Touch-sensitive screens similar to those on personal computers are used instead of keyboards or pushbuttons on some late-model systems. Ahead-up display (HUD) is a secondary display system that projects video images onto the windshield. The GM night vision system is a head-up display (HUD) system that projects useful vehicle information in front of the driver near the windshield.