Instrument Cluster / Carrier: Description and Operation

The instrument cluster contains an analog speedometer, tachometer, fuel gauge and engine coolant temperature gauge. The instrument cluster receives the information hardwired. Each time the ignition switch is turned from OFF to ON, the following instrument cluster warning indicators will prove out:
- airbag
- Anti-lock Brake System (ABS) (if equipped)
- brake
- charging system
- door ajar
- check engine (MIL)
- low coolant (if equipped)
- low fuel
- low oil pressure
- safety belt
- traction control (if equipped)
- anti-theft
- check fuel cap
- check transmission

Engine Coolant Temperature Gauge
The engine coolant temperature gauge indicates the engine coolant temperature based on the operating resistance range from the engine coolant temperature sender. If the engine coolant temperature is low, the sender resistance is high. If the engine coolant temperature is high, the sender resistance is low. The engine coolant temperature sender resistance range should be between 18.3 ohms and 275 ohms.

Fuel Gauge
The fuel gauge receives the fuel level resistance from the fuel level sensor, part of the fuel pump module. To prevent the fuel gauge pointer from fluctuating as a result of excessive movement of fuel in the fuel tank, the fuel indicator module provides a delay to the fuel gauge. If the fuel level is low, the resistance in the fuel level sensor will be low, causing the gauge to indicate empty (E). When the fuel level is high, the resistance in the fuel level sensor is high, and the gauge indicates full (F). A new fuel gauge and the fuel indicator module must be installed together. The fuel indicator module also turns on the low fuel indicator when the fuel gauge shows approximately 1/6 of a tank of fuel remaining or less.

Flex-Fuel Module
The flex-fuel module is a DC-AC-DC converter. It acts as an interface between the fuel pump module and the instrument cluster fuel gauge. The flex-fuel module is located in the instrument panel, on the right side of the steering column, just behind the Integrated Control Panel (ICP).

Speedometer/Odometer
The speedometer and odometer provide speed information based on a speed/rpm pulse signal from the Powertrain Control Module (PCM).

Warning Indicators

Air Bag
The air bag warning indicator is controlled by the Restraint Control Module (RCM). When starting the vehicle, the air bag warning indicator illuminates and remains lit for six seconds. The indicator only illuminates after starting the vehicle if a Supplemental Restraint System (SRS) malfunction is detected.

Anti-lock Brakes
The anti-lock brake warning indicator illuminates when the anti-lock brake control module detects a fault in the system.

Brake System
The brake system warning indicator has a dual function. It illuminates when the parking brake is applied or when a low brake fluid condition exists in the brake master cylinder reservoir. The brake system warning indicator will illuminate when there is a pressure differential between the front and rear brake hydraulic systems.

Charging System
The charging system indicator illuminates whenever the generator output is insufficient to maintain the battery state of charge or if the generator output is too high. Under a no charge condition or with the ignition ON and the engine off, the PCM provides a ground to the instrument cluster illuminating the charge system indicator. The PCM, upon receipt of a charge signal, removes the ground to the instrument cluster turning off the charge system indicator.

Low Fuel
The low fuel warning indicator is controlled by the fuel indicator module and warns the driver when the fuel level is 1/6 of a tank or lower.

Check Transmission
The check transmission illuminates if a fault is detected in the transmission.

Safety Belt
The safety belt indicator is directly wired to the Generic Electronic Module (GEM). The GEM controls the safety belt indicator based on the signal it receives from the safety belt buckle switch. The safety belt indicator illuminates when the safety belt is not buckled, closing the safety belt buckle switch.

Check Fuel Cap
The PCM monitors pressure in the fuel evaporative system and detects massive or critical losses of pressure. When a critical loss of pressure in the fuel evaporative system is detected, the PCM provides a ground and the instrument cluster illuminates the check fuel cap indicator.