The instrument cluster (IPC) indicators are illuminated by one of the following methods:

The air bag indicator is a light emitting diode (LED) display in the instrument cluster but is operated by a designated circuit from the inflatable restraint sensing & diagnostic module (SDM). A diagnostic trouble code (DTC) will be stored in the SDM for any related system malfunction.

The anti-lock indicator is a display in the IPC and is operated by the electronic brake control module (EBCM). The anti-lock indicator will turn ON for 3 seconds when the ignition switch is placed in the RUN position. The anti-lock indicator will also turn ON when the IPC receives class 2 information from the requesting the anti-lock indicator to be turned ON or if the cluster loses class 2 communication with the EBCM. A diagnostic trouble code (DTC) will be stored in the EBCM for any related system malfunction.

The brake warning indicator, in the instrument cluster, is operated by the electronic brake control module (EBCM) and the body control module (BCM). It indicates a low fluid pressure condition exists in the brake system when the brake warning indicator finds ground through the pressure differential switch in the combination valve. It also indicates the park brake is applied when the brake warning indicator finds ground through the park brake switch. When the park brake is set with the ignition switch in the RUN position, the park brake indicator will flash. The BCM will command the indicator ON in order to indicate that the park brake is engaged. The EBCM will command the Brake indicator ON in order to indicate a low fluid pressure condition.

The cruise indicator is a lamp in the instrument cluster. When the cruise control has been engaged, the VCM/PCM uses class 2 communication in order to send a message to the instrument cluster to turn ON the cruise indicator lamp.

The high beam indicator is an incandescent lamp in the instrument cluster. A class 2 serial data message from the BCM is sent to the instrument cluster when the high beams are turned on. The BCM senses the input and sends the message to the instrument cluster to turn the indicator on.

The left turn signal indicator is an incandescent lamp in the instrument cluster . The left turn signal indicator lamp has a designated circuit to the cluster from the turn signal switch and the turn signal flasher.

The right turn signal indicator is an incandescent lamp in the instrument cluster. The right turn signal indicator lamp has a designated circuit to the cluster from the turn signal switch and the turn signal flasher.

The seat belt indicator is a display in the instrument cluster. The body control module (BCM) uses class 2 serial data communication in order to turn the seat belt indicator on and off. This vehicle has an enhanced seat belt warning system. This system activates a warning lamp for about 75 seconds and an audible warning for about eight seconds when the ignition switch is turned to the RUN position and the drivers seat belt is not buckled. The warning lamp will be constant for the first 20 seconds, then flash for the remaining 55 seconds. The audible warning only turns on, and will stay on when the drivers seat belt is not fastened during the eight second time period. If the drivers seat belt is buckled when you turn the ignition switch to the RUN position, the warning lamp will not illuminate and the audible warning stays off. If the drivers seat belt buckle is unbuckled prior to eight seconds, the audible warning will turn on for the balance of the eight second delay.

The service engine soon (SES) indicator is in the instrument cluster but is operated by a designated circuit from the VCM/PCM. The SES should turn on with the ignition switch in the RUN position and the engine off. The lamp should turn off 1 to 5 seconds after the engine starts. If the lamp stays on or turns on while driving, service to the emission control system may be required. Refer to

The TOW/HAUL indicator is in the instrument cluster. When the TOW/HAUL button is depressed at the end of the shift lever, the BCM uses class 2 serial data communication in order to send a message to the instrument cluster to turn ON the TOW/HAUL indicator lamp.

The up-shift indicator is in the instrument cluster. The up-shift indicator will turn ON when the instrument cluster receives class 2 serial data information from the VCM/PCM requesting the up-shift indicator to be turned ON. The up-shift indicator in the instrument cluster turns on in order to indicate optimum shift points for maximum fuel economy. When this lamp turns on, shift the transmission to the next higher gear range, if the conditions permit.

Control of the up-shift indicator is a function of the PCM/VCM. Several conditions are monitored, such as the engine speed, load, and the throttle position to turn on the lamp. If the lamp is erratic or inoperative, verify the integrity of the circuit. Then use the scan tool to command the up-shift lamp on and off. If the scan tool can command the up-shift lamp on and off, replace the PCM/VCM if no problem is found.

The 4WD indicator is in the instrument cluster. When the shift lever is placed in 4WD, the VCM/PCM uses class 2 serial data communication in order to send a message to the instrument cluster when to turn ON the 4WD-indicator lamp.

This cluster contains a message center module which can sequentially display up to 30 messages or ISO symbols. In the event that more than one message is required to be displayed at the same time in the message center, the messages will be sequentially displayed to the driver in five second intervals or fifteen second intervals.

Communication Type

A message using the class 2 communication type is turned on and off in the cluster by a class 2 serial data message from the applicable module (i.e. BCM, PCM/VCM).

A message using the discrete wire communication type is turned on and off in the cluster by a wire from the applicable sensor (i.e. oil pressure/low washer switch).

Once An Ignition Cycle

A message is sequenced into the message center display once per ignition cycle for 15 seconds.

Continuous

A message is sequenced into the message center display for five second intervals. If only one message is to be displayed in the message center, the message will not blink between these intervals so that the message appears to be displayed continuously. If another message is added, the display will cycle between messages. The new message will then be displayed for a five second interval.

Battery Charge Fault

The battery charge fault message is a class 2 serial data message from the PCM/VCM. The conditions for turning on the battery message in the message center are described below.

CARGO LAMP ON

The CARGO LAMP ON message is sent to the cluster as a class 2 serial data message from the body control module (BCM). The CARGO LAMP ON message will be added to the message center display when the cargo lamp switch is toggled on and removed from the message center when the switch is toggled again.

CHECK COOLANT TEMP

The coolant temperature is sent to the cluster as a class 2 serial data value from the PCM/VCM. The cluster turns on the CHECK COOLANT TEMP message based on the coolant temperature. If the coolant temperature is greater than 121°C (250°F) it will be added to the message center and removed when the coolant temperature drops below 118°C (245°F).

CHANGE ENGINE OIL

The CHANGE ENGINE OIL message is sent to the cluster as a class 2 serial data message from the VCM/PCM. This message is designed to come when it is time to change the engine oil and filter usually between 3,000 to 7,500 miles and/or three months to twelve months whichever comes first. Under severe conditions, the indicator may come on sooner than 3,000 miles or three months. To reset the CHANGE ENGINE OIL message, turn the ignition switch to the RUN position with the engine off. Fully press and release the accelerator pedal three times within five seconds. The CHANGE ENGINE OIL message will flash for five seconds to notify the driver the system has been reset. Exactly when the indicator comes ON is based on a complex formula that takes into account some of the following vehicle inputs:

CHECK ENG OIL LEVEL

The CHECK ENG OIL LEVEL message is sent to the cluster as a class 2 serial data message from the VCM/PCM. The CHECK ENG OIL LEVEL message will be added to the message center display when the VCM/PCM receives the engine oil level low from the engine oil level switch.

CHECK ENG OIL PRESSURE

The Check Eng Oil Pressure message input to the IPC will be a discrete wire from the oil pressure sensor. The oil pressure sensor output signal must be a variable resistance to ground, as measured at the IPC connector. The conditions for asserting the Check Eng Oil Pressure message in the message center display are described below.

ENGINE OVER--HEATED

The coolant temperature is sent to the cluster as a class 2 serial data value from the PCM/VCM. The cluster turns on the ENGINE OVER--HEATED message based on the coolant temperature. If the coolant temperature is greater than 128°C (262°F) it will be added to the message center and removed when the coolant temperature drops below 125°C (257°F).

LOW COOLANT

The LOW COOLANT message is sent to the cluster as a class 2 serial data message from the VCM/PCM. The LOW COOLANT message will be added to the message center display when the VCM/PCM receives the coolant level low from the engine coolant level switch in the fill tank.

LOW FUEL

The LOW FUEL message is a class 2 serial data message from the PCM/VCM to the instrument cluster based on the fuel level (% Fuel). The conditions for adding the LOW FUEL message to the message center are described below.

LOW WASHER FLUID

The LOW WASHER FLUID message input to the cluster is a discrete wire from the washer bottle switch. The LOW WASHER FLUID message shall be displayed when the circuit to the cluster is grounded by the washer bottle switch continuously for 30 seconds. The LOW WASHER message will be displayed continuously for 15 seconds and only once per ignition cycle, and then removed from the message center display.

REDUCED ENGINE POWER

The REDUCED ENGINE POWER message is sent to the cluster as a class 2 serial data message from the VCM/PCM. The REDUCED ENGINE POWER message will be added to the message center display when the engine is over-heated.

SECURITY

The SECURITY message is a class 2 serial data message from the body control module (BCM). The SECURITY message can be commanded on by both Passlock and content theft deterrent (CTD) systems. The SECURITY message can be on continuously, or flashing.

SERVICE 4WD

The SERVICE 4WD message is sent to the cluster as a class 2 serial data message from the automatic transfer case (ATC) module. The SERVICE 4WD message will be added to the message center display any time a diagnostic trouble code is set.

TRANS FLUID HOT

The transmission fluid temperature is sent to the cluster as a class 2 serial data value from the PCM/VCM. The cluster turns on the TRANS FLUID HOT message based on the transmission fluid temperature. If the transmission fluid temperature is greater than 130°C (266°F) it will be added to the message center and removed when the transmission fluid temperature drops below 127°C (260°F).

TRANS HOT...IDLE ENGINE

The transmission fluid temperature is sent to the cluster as a class 2 serial data value from the PCM/VCM. The cluster turns on the TRANS HOT...IDLE ENGINE message based on the trans fluid temperature. If the transmission fluid temperature is greater than 135°C (275°F)it will be added to the message center and removed when the transmission fluid temperature drops below 132°C (270°F).