Instrument Panel, Gauges and Warning Indicators: Description and Operation
Gauges and IndicatorsHow the Circuit Works
The indicator lights are controlled by relative conditions in their associated systems. Refer to each associated system to see its entire schematic. For the following indicators, the information supplied to the gauge control module is received via the data lines.
- ABS Indicator
- Brake System Indicator
- Charging Indicator
- Coolant High Temperature Warning Light
- Coolant Low Temperature Warning Light
- Maintenance Required Indicator
- MIL Indicator
Fuel Gauge and Low Fuel Indicator Light
WARNING: Do not smoke while working on the fuel system. Keep open flame away from the work area. Drain fuel only into an approved container.
The fuel gauge is controlled by the CPU in the gauge assembly. The fuel gauge sending unit (part of the fuel tank unit) sends a fuel level signal to the CPU in the gauge assembly through the YEL/BLK wire (cavity A 18). The signal varies depending on the position of the float in the fuel tank which changes the resistance of the sending unit. When the CPU determines that the fuel level is low, it turns on the low fuel indicator. The sending unit's resistance varies as shown.
Speedometer and Odometer
The speedometer and odometer are controlled by the CPU in the gauge assembly. The CPU receives a pulsing input from the VSS (M/T) or from the PCM (A/T). The pulse rate increases as the car accelerates. The frequency and duration of these input pulses are measured by the CPU.
Tachometer
The tachometer is controlled by the CPU in the gauge assembly. The CPU receives a pulsing input from the PCM. The frequency and duration of these input pulses are measured by the CPU. The CPU controls the tachometer indicating the engine speed.