Instrument Panel, Gauges and Warning Indicators: Description and Operation

CIRCUIT OPERATION

See the circuit referred to for the complete operation of an Indicator and the other components that work with it. Only the Indicators and displays that do not appear in other schematics are described in this area.


OIL PRESSURE Indicator

The OIL PRESSURE Indicator is linked to the Oil Pressure Sensor and the Oil Pressure Switch through the Body Computer Module (BCM). When the oil pressure drops below 4 psi, the Oil Pressure Switch closes, grounding the oil pressure input to the BCM. The BCM sends this information over the serial data line to the Instrument Panel Cluster (IPC). The IPC reads the serial Data Line and turns on the OIL PRESS Indicator.

TEMP Indicator

The TEMP Indicator is linked to the Coolant Temperature Sensor through the Powertrain Control Module (PCM) and the BCM. The PCM is constantly reading the resistance of the Coolant Temperature Sensor and sending this information to the BCM over the serial Data Line. The BCM then sends this information to the Instrument Panel Cluster. When the engine coolant temperature causes the resistance of the Coolant Temperature Sensor to drop below a certain level, the BCM through the serial data line, communicates to the IPC to light the TEMP Indicator.


STOP ENGINE-TEMP Indicator

The STOP ENGINE-TEMP Indicator receives battery voltage from Fuse 1 when the Ignition is switched to RUN. When the vehicle engine overheats, the Engine Metal Temperature Switch closes, completing a current path to ground. The Indicator lights and the temperature chime sounds.

Hi Beam Indicator

The Hi Beam Indicator is linked to the Headlight Dimmer Switch through the BCM. The ECM constantly reads the Hi Beam input line from the Headlight Dimmer Switch. When the Hi Beams are turned on, the Hi Beam input to the BCM is grounded. The ECM knows that the Hi Beams are on and sends this information to the Instrument Panel Cluster. The IPC then turns on the Hi Beam Indicator.


Speedometer/Odometers

The Vehicle Speed Sensor sends the speed signal to the PCM in the form of AC electrical voltage. The PCM modifies and sends this signal to the Speedometer and Odometers. The speed and distance reading can be displayed in either English or metric values.


Tachometer Display

The Tachometer receives its signal from the Electronic Spark Timing (EST) Distributor. The Instrument Panel Cluster processes the raw signal and displays the engine rpm on the Tachometer display.


Oil Pressure Display

The Oil Pressure Display is tied to the Oil Pressure Sensor and the Oil Pressure Switch through the ECM. The ECM reads the oil pressure input line and sends this information to the Instrument Panel cluster through the serial Data Line. The IPC displays the oil pressure on the Oil Pressure display.

Coolant Temperature Display

The Coolant Temperature display is tied to the Coolant Temperature Sensor through the PCM and BCM. The PCM is constantly reading the resistance of the Coolant Temperature Sensor and sending this information to the BCM over the serial Data Line. The BCM then sends this information to the Instrument Panel Cluster. The IPC displays the coolant temperature on the Coolant Temperature display.


Fuel Gage Display

The Fuel display is tied to the Fuel Tank Sender in the Fuel Tank Unit through the BCM. The ECM constantly monitors the voltage of the Fuel Tank Senders and sends this information to the Instrument Panel Cluster over the serial Data Line. The IPC displays the fuel level on the Fuel Gage display.


PRND321 Display (Digital Cluster Only)

The PRND321 Display is tied to the Transaxle Position Switch through the BCM. The ECM receives the necessary gear selector switch position inputs and sends this information to the Instrument Panel Cluster (IPC) through the serial Data Line. The IPC then lights the appropriate gear selector box. The Transaxle Position Switch uses 4 inputs to the BCM and creates a unique digital signal for each gear by pulling the inputs to ground which results in a low signal or by not pulling the input to ground which results in a high signal. The voltage level of each input is represented in ECM data BD41 as: 0 = grounded, 1 = not grounded.