A Preliminary Information

IMPORTANT: The following steps must be completed before using the symptom tables.

1. Perform Diagnostic System Check - Instrument Cluster before using the Symptom Tables in order to verify that all of the following are true: Diagnostic System Check
^ There are no DTCs set.
^ The control module(s) can communicate via the serial data link.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following:
^ Instrument Panel Cluster (IPC) Description and Operation
^ Indicator/Warning Message Description and Operation
^ Audible Warnings Description and Operation

Visual/Physical Inspection
^ Inspect for aftermarket devices which could affect the operation of the Instrument Cluster or Audible Warning Systems. Refer to Checking Aftermarket Accessories in Diagrams.
^ Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
^ Inspect for proper fluid levels.

Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent and Poor Connections in Diagrams.

Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

Gauges and Odometer
^ Engine Coolant Temperature Gage Inaccurate or Inoperative
^ Engine Oil Pressure Gage Inaccurate or Inoperative
^ Fuel Gage Inaccurate or Inoperative (Single Tank L65 Diesel Engine) or Fuel Gage Inaccurate or Inoperative (Dual Tank L65 Diesel Engine) or Fuel Gage inaccurate or inoperative (Single Tank 8.1L Gasoline Engine) or Fuel Gage Inaccurate or Inoperative (Dual Tank 8.1L Gasoline Engine)
^ Range Selector Display Inoperative or Displays Incorrect Range in Automatic Transmission 4L80-E
^ Speedometer and/or Odometer Inaccurate or Inoperative (8.1L Gasoline Engine) or Speedometer and/or Odometer Inaccurate or Inoperative (L65 Diesel Engine)
^ Tachometer inaccurate or inoperative (8.1L Gasoline Engine) or Tachometer Inaccurate or Inoperative (L65 Diesel Engine)
^ Volt Gage Inaccurate or Inoperative

Indicators
^ ABS Indicator Always On in Anti lock Brake System
^ ABS Indicator Inoperative in Antilock Brake System
^ Brake Warning Indicator Always On (DRL Equipped) or Brake Warning Indicator Always On (Without DRLs) in Hydraulic Brakes
^ Brake Warning Indicator Inoperative (Without DRLs) or Brake Warning Indicator Inoperative (DRL Equipped) in Hydraulic Brakes
^ Charge Indicator Always On (8.1L) or Charge Indicator Always On (6.5L) in Starting and Charging
^ Charge Indicator Inoperative (8.1L) or Charge Indicator Inoperative (6.5L) in Starting and Charging
^ Daytime Running Lamps (DRL) Indicator Inoperative in Lighting and Horns
^ Fasten Safety Belt Indicator/Chime Always On in Seat Belts
^ Fasten Safety Belt Indicator/Chime Inoperative in Seat Belts
^ High Beam Indicator Inoperative in Lighting and Horns
^ Low Engine Coolant Indicator Always On in Cooling System
^ Security Indicator Always On or Flashing in Antitheft and Alarm Systems
^ Security Indicator Inoperative in Antitheft and Alarm Systems
^ Turn Signal Lamps and/or Indicators Always On or Flashing in Lighting and Horns
^ Turn Signal Lamps and/or Indicators Inoperative in Lighting and Horns
^ Water-in-Fuel Lamp Always On in Computers and Control Systems - 6.5L (L65)
^ Water-in-Fuel Lamp Inoperative in Computers and Control Systems - 6.5L (L65)

Instrument Cluster Dimming
^ Interior Backlighting Inoperative in Lighting and Horns
^ Interior Backlighting Inoperative in Lighting and Horns
^ Interior Backlighting Does Not Dim in Lighting and Horns

Audible Warning
^ Chime Always On
^ Chime Inoperative