Instrument Cluster / Carrier: Description and Operation

The instrument cluster is a configurable, Hybrid Electronic Cluster (HEC) that contains a microprocessor, gauges, indicator lamps, backlighting lamps and internal circuitry. The instrument cluster is non-repairable at the dealership level with the exception of the warning indicator bulb, the backlighting bulb and the instrument cluster lens replacement. The instrument cluster utilizes hardwired circuitry, the Standard Corporate Protocol (SCP), and UART Based Protocol (UBP) communication networks. Communication using the SCP network transmits and receives data between the instrument cluster and the PCM. Communication using the UBP network utilizes data transmitted and received by the instrument cluster and the body security module, driver seat module and the Electronic Air Temperature Control (EATC).

It is very important to understand:
^ where the input originates from.
^ all the information necessary in order for a feature to operate.
^ which module(s) receive(s) the input or command message.
^ whether the module which received the input controls the output of the feature, or whether it outputs a message over the SCP or UBP network to another module.
^ which module controls the output of the feature.
^ whether the module which received the input controls the output of the feature, or whether it outputs a message over the SCP or UBP network to another module.
^ which module controls the output of the feature.

The instrument cluster carries out a display prove-out to verify that the warning/indicator lamps and monitored systems are operating correctly. When the ignition switch is turned to the ON position with the engine off, the following indicators will illuminate:
^ 4x4 LOW indicator
^ 4x4 high indicator
^ BRAKE warning indicator
^ Malfunction Indicator Lamp (MIL) indicator
^ check fuel cap indicator
^ CHECK GAGE warning indicator
^ CK SUSP indicator
^ door ajar indicator
^ low fuel warning indicator
^ safety belt warning indicator

Gauge Indication Systems
The instrument cluster and gauges are non-repairable at the dealership level. No adjustment, calibration, or maintenance is required for any gauges.

Instrument Cluster Replacement

CAUTION: When installing a new instrument cluster, the instrument cluster must be re-configured.

When installing a new instrument cluster, contact a Ford authorized instrument cluster repair facility.

Speedometer
The instrument cluster is hardwired to the Four Wheel Anti-lock Brake System (4WABS) module. The instrument cluster micro-processor monitors the VSS data from the 4WABS module and commands the speedometer with a corresponding movement of the pointer. The vehicle speed signal is generated by the rear anti-lock brake sensor and sent to the 4WABS module. The 4WABS module sends the vehicle speed signal via circuit 679 (GY/BK) to all systems that require a vehicle speed signal input.

Odometer
A million-mile tamper-resistant odometer is standard. New speedometers have a reset table odometer.

NOTE: When installing a new instrument cluster some state laws require that the new odometer must register the same as the removed odometer.

If the actual vehicle mileage cannot be determined, the repair centers are able to supply odometers set to "0" miles. An odometer mileage sticker must display the estimated vehicle mileage and be affixed to the driver door jamb. The odometer mileage sticker is available through the parts distribution center.

Trip Odometer
The trip odometer indicates how many miles the vehicle has been driven since the last reset.

Fuel Gauge
The instrument cluster is hardwired to the fuel sending unit, which is a variable resistor controlled by the action of a float arm. When the fuel level is low, resistance in the unit is low. When the fuel level is high, the resistance is high. The instrument cluster micro-processor monitors the input from the fuel sender and commands the fuel gauge indication according to the fuel level data.

Temperature Gauge
The instrument cluster receives the temperature signal from the PCM via the Standard Corporate Protocol (SCP) network.

Transmission Temperature Gauge (Automatic Transmission Only)
The instrument cluster receives the transmission temperature information from the PCM via the SCP network. The instrument cluster micro-processor monitors the transmission temperature data and commands the gauge indication with a corresponding movement of the pointer.

Oil Pressure Gauge
The instrument cluster is hardwired to the oil pressure sender unit. The instrument cluster micro-processor monitors the oil pressure data and commands the oil pressure gauge indication with a corresponding movement of the pointer. The oil pressure indicator sender unit consists of a diaphragm and contact points. The contact points are closed with oil pressure causing the gauge to indicate NORMAL oil pressure. With no oil pressure, the contacts open and the gauge indicates low oil pressure.

Voltage Gauge (Manual Transmission Only)
The voltage gauge displays the system voltage as measured at the instrument cluster run input.

Tachometer
These vehicles are equipped with a 6,000 rpm tachometer. The instrument cluster receives the tachometer data from the PCM via the SCP network and commands the tachometer according to the data.

Warning Indicators

Charging System Indicator
The ignition switch contacts are closed, battery current flows through the charging system indicator and the parallel resistor (390 ohms) to the voltage regulator. Internal circuitry in the voltage regulator provides a ground path to the instrument cluster and the indicator illuminates. When the generator builds up enough voltage to energize the voltage regulator, voltage is applied to the ground side of the indicator effectively removing the ground path and turning the indicator off.

Brake Warning Indicator
The red brake warning light (BRAKE) is used to indicate a low fluid level, brake concern, a parking brake that is not fully released, or an Anti-lock Brake System (ABS) fault. The brake fluid level switch is located in the brake fluid reservoir.

ABS Warning Indicator
The yellow brake warning indicator is used to indicate a concern or deactivation of the ABS. It illuminates when triggered by the ABS control module and stays illuminated as long as the concern remains in the system.

Malfunction Indicator Lamp (MIL) Indicator
The malfunction indicator lamp (MIL) indicator is illuminated when a Diagnostic Trouble Code (DTC) is sensed in the closed loop by the Powertrain Control Module (PCM). The instrument cluster receives engine data from the PCM via the SCP network.

Air Bag Warning Indicator
The instrument cluster is hardwired to the restraint control module. If an air bag system DTC is detected, the restraint control module provides a ground path to the instrument cluster and the air bag indicator is illuminated.

Safety Belt Warning Indicator
The safety belt warning indicator is powered through the instrument cluster and is grounded through the safety belt retractor switch. When the safety belt is extended, indicating a buckled condition, the switch will open to the instrument cluster and the safety belt indicator is extinguished. When the safety belt is retracted, indicating an unbuckled condition, the switch closes and provides a ground to the instrument cluster and the safety belt indicator is illuminated.

Low Fuel Warning Indicator
The low fuel warning indicator is controlled by the instrument cluster microprocessor and illuminates when the fuel level drops below approximately one-sixteenth of a tank or 4-8 L (1-2 gal).

Door Ajar Indicator
On vehicles that are equipped with remote keyless entry, the door ajar switches provide a ground signal to the body security module which subsequently provides a ground signal to the instrument cluster via the UBP network and illuminates the door ajar indicator. On vehicles not equipped with remote keyless entry, the door ajar switches are hardwired to the instrument cluster and provide the ground to illuminate the door ajar indicator.

High Beam Indicator
The instrument cluster provides a ground for the high beam indicator. The multifunction switch provides a switched power source to the instrument cluster to illuminate the high beam indicator when in the high beam position. When the high beams are activated, the multifunction switch sends a power signal to the instrument cluster and illuminates the high beam indicator.

Speed Control Indicator
The instrument cluster provides power to the speed control indicator. The speed control indicator is controlled by the speed control module. When the speed control is engaged, the speed control module provides the instrument cluster with a ground signal and illuminates the speed control indicator.

Theft Indicator
The instrument cluster provides the THEFT indicator with power. The theft indicator is hardwired to the PATS module and will flash when the PATS system is activated.

Check Air Filter Indicator
The check air filter indicator is hardwired to the air filter indicator switch (located in the air filter housing) and monitors the air flow through the air cleaner. The air filter indicator is powered by the instrument cluster and when air flow is low, the air filter indicator switch provides a ground to the instrument cluster illuminating the check air filter indicator.

Check Gauge Warning Indicator
The check gauge warning indicator will illuminate when any of the three following conditions exist:
^ if the engine oil pressure drops below approximately 42 kPa (6 psi).
^ if the engine temperature exceeds approximately 121°C (250°F).
^ if the transmission temperature (automatic transmission only) reaches approximately 135°C (275°F).

Check Fuel Cap Indicator
The check fuel cap indicator is used to indicate significant leaks in the fuel tank evaporative system due to a loose fuel cap. Fuel tank pressure is monitored by the PCM and once a leak is detected, the PCM signals a fault to the instrument cluster via the SCP network. Once the PCM has detected a loose fuel cap and the check fuel cap indicator is illuminated, the check fuel cap indicator will remain illuminated until the fuel cap is secured and the vehicle has been running for several minutes or the ignition has been cycled once.

CK SUSP Indicator
The CK SUSP indicator is powered through the instrument cluster. When the air suspension is activated, the suspension control module provides the ground to the instrument cluster and illuminates the CK SUSP indicator.

4x4 High/4x4 LOW Indicators
The 4x4 high and 4x4 LOW indicators are both hardwired to the instrument cluster from the 4x4 control module when equipped with electronic shift, or from the 4x4 control switch when equipped with manual shift. The instrument cluster provides the 4x4 indicators with power and the 4x4 control module, or 4x4 switch, provide the ground depending on whether 4x4 high or 4x4 low is selected.

CHECK GAGES Warning Indicator
The CHECK GAGES warning indicator monitors the coolant temperature and the engine oil pressure. The indicator will illuminate if the SCP coolant temperature data is missing or invalid, if the engine temperature reaches 121°C (249.8°F) or higher, or if the engine oil pressure is low.