Principles of Operation (How Does It Work)

The Hybrid Electronic Cluster (HEC) receives its input and output signals hardwired or over the ISO 9141 K bus line. The HEC carries out a display proveout to verify that warning/indicator lamps and monitored systems are functioning correctly. When the ignition switch is in the ON position with the engine off, the following warning indicators will illuminate or be displayed:
^ Anti-lock Brake System (ABS)
^ Air bag (if equipped)
^ Charge system
^ Low coolant
^ Low fuel
^ Low washer fluid level
^ Safety belt (60 second proveout)
^ Malfunction Indicator Lamp (MIL)

The HEC controls the illumination of the following indicator lamp module warning indicators:
^ Maintenance interval warning indicator
^ Frost warning indicator (orange)
^ Ice warning indicator (red)
^ Brake pad wear
^ Door/liftgate ajar

The bulb warning indicator is controlled by the bulb outage module.

Hybrid Electronic Instrument Cluster (HEC) Gauges

Engine Coolant Temperature Gauge
Engine coolant temperature information is received by the HEC from the engine coolant temperature (ECT) sensor (2.0L engine) or ECT switch (2.5L engine). If the engine coolant temperature signal is missing or invalid, the HEC will move the engine coolant gauge pointer to the cold position.

Fuel Gauge
The HEC receives the fuel level information from the fuel sending unit (part of the fuel pump module). When the fuel level is low, the resistance is low. When the fuel level is high the resistance is high.

Speedometer
The HEC receives the vehicle speed signal from the Vehicle Speed Sensor (VSS).

Tachometer
The HEC receives tachometer information from the powertrain control module (PCM). If the RPM information sent to the HEC is invalid or missing, the HEC will default the tachometer to 0.

Warning Indicators

Air Bag Warning Indicator
The air bag warning indicator is controlled by the air bag module. REFER to Air Bag Systems.

ABS Indicator
The HEC Anti-lock Brake System (ABS) indicator is hardwired directly to the ABS module. The ABS indicator should prove out when the ignition switch is turned ON. An open, a short to battery, or any ABS failure will illuminate the ABS indicator.

Brake System Warning Indicator
The brake system warning indicator has multiple functions. The brake system warning indicator proves out when the ignition switch is in the START position, thus grounding the circuit. The indicator illuminates if the brake fluid is low or if the parking brake is set. If both the ABS indicator and the brake system warning indicator are illuminated, a concern exists in the ABS module.

Charging System Indicator
The charging system is connected directly to the generator. If low voltage is detected, the charging system indicator illuminates.

Fog Lamp Indicator
The HEC fog lamp indicator is directly hardwired to the fog lamp switch. The headlamp switch must be turned ON for the fog lamps and indicator to operate.

The High Beam Indicator
The HEC high beam indicator is hardwired directly to the multifunction switch.

Left And Right Turn Signal Indicators
The HEC left and right turn signal indicators are hardwired directly to the multifunction switch.

Headlamp On Indicator
The HEC headlamp on indicator is hardwired directly to the headlamp switch.

Malfunction Indicator Lamp (MIL)
The HEC Malfunction Indicator Lamp (MIL) is controlled by the powertrain control module (PCM). after the engine is started, the MIL remains on for a prove out duration of three seconds.

Low Oil Pressure Indicator
The HEC low oil pressure indicator is hardwired to the engine low oil pressure switch. With the ignition switch in the ON position, the low oil pressure indicator should be illuminated. After the engine is started and the oil pressure builds up, the oil pressure switch opens and turns off the oil pressure indicator.

Safety Belt Warning Indicator
The HEC safety belt indicator illuminates if the driver safety belt is not fastened when the ignition switch is turned ON. The HEC receives the safety belt status hardwired from the central timer module (CTM). The safety belt indicator will turn off after 60 seconds from when the engine was started, regardless of the driver safety belt status.

Traction Control (TC) Indicator
The HEC TC indicator is controlled by the ABS/TC module. The indicator is illuminated when the TC is active. The traction control feature can be disabled by depressing the TC OFF button.

HEC Indicator Lamp Module Warning Indicators
The bulb out warning indicator is controlled directly by the bulb outage module. With the ignition switch ON the bulb out warning indicator will illuminate for about three seconds then prove out. If the brake pedal is not depressed, the bulb out warning indicator remains on.

Brake Pad Wear Indicator
The HEC receives information directly from the:
^ left front brake pad sensor
^ right rear brake pad sensor
^ left rear brake pad sensor
The sensors are normally closed, thus grounding the circuits to the HEC. If a sensor opens or if an open or short to battery occurs to the circuit the brake pad wear indicator illuminates.

Ice Warning Indicator
The ice warning indicator is controlled by the HEC. The ice warning sensor is hardwired directly to the HEC. When the outside temperature drops below 0°C (32°F), the HEC illuminates the indicator.

Frost Warning Indicator
The frost warning indicator is controlled by the HEC. The ice warning sensor is hardwired directly to the HEC. When the outside temperature drops below 4°C (40°F), the HEC illuminates the frost warning indicator.

Maintenance Interval Warning Indicator
The maintenance interval warning indicator is controlled by the HEC. The HEC illuminates the indicator advising a schedule maintenance (which is dependant on time or distance). The indicator is reset by placing the ignition switch in position II and depressing the SELECT and UNITS buttons simultaneously for five seconds until the maintenance light extinguishes.