INFO - IP CLUSTER REPLACEMENT DIAGNOSTIC PROCEDURES. Chevrolet Corvette 1998

REVISION: 10/09/98 DIVS INVL 1 7

THIS BULLETIN IS BEING REVISED TO DELETE STEP #5, UNDER "SEPARATELY SERVICEABLE PARTS". THE UV BULB IS NOT AVAILABLE. PLEASE DISCARD CORPORATE BULLETIN NUMBER 83-83-15 (SECTION CHASSIS/BODY ELECTRICAL) ______________________________________________________________________

SUBJECT: INFORMATION - IP CLUSTER REPLACEMENT DIAGNOSTIC PROCEDURES

MODELS: 1997-98 CHEVROLET CORVETTE

EXAMINATION OF PARTS RETURNED BY DEALERS TO THE WARRANTY PARTS CENTER (WPC) HAS SHOWN THAT MANY CLUSTERS ARE BEING REPLACED UNNECESSARILY. BECAUSE THE CLUSTER IS NOT REPAIRABLE, EXTRA PRECAUTIONS SHOULD BE TAKEN BEFORE REPLACING THE CLUSTER.

FOLLOWING ARE SEVERAL ITEMS THAT SHOULD BE CHECKED BEFORE THE CLUSTER IS REPLACED.

NORMAL OPERATION -

SEVERAL CLUSTERS WERE REPLACED FOR NORMAL CONDITIONS, SUCH AS THE CLUSTER LIGHTS DIMMING WHEN DRIVING THROUGH A TUNNEL. THE OWNER'S MANUAL AND/OR SERVICE MANUAL SHOULD ALWAYS BE CHECKED TO INSURE THAT WHAT THE CUSTOMER IS REPORTING IS NOT A NORMAL CONDITION.

LOSS OF COMMUNICATION -

ABOUT 70% OF THE CLUSTERS REPLACED WERE FOR LOSS OF COMMUNICATION. THE VARIOUS MODULES IN THE VEHICLE COMMUNICATE WITH EACH OTHER, AND IF A PROBLEM IS FOUND, ONE OR MORE "U" CODES CAN BE STORED IN VARIOUS MODULES. THE CLUSTER STORES MORE CODES THAN OTHER MODULES AND IS OFTEN REPLACED BECAUSE IT HAS THE MOST CODES. ACTUALLY, THE FACT THAT IT IS STORING CODES MEANS THAT IT IS OPERATING PROPERLY.

THE BEST METHOD FOR FINDING THE PROBLEM WHEN "U" CODES ARE STORED, IS TO USE THE "DATA LINK COMMUNICATION DIAGNOSTIC SYSTEM CHECK" ON PAGE 8-404 OF THE 1998 SERVICE MANUAL.

INTERMITTENT LOSS OF POWER -

THE CLUSTER GOES THROUGH A START-UP ROUTINE EACH TIME THE IGNITION IS TURNED ON. ALL THE LIGHTS TURN ON AND OFF AND THE GAUGES SWING THROUGH A COMPLETE ARC. THIS IS CALLED THE "START-UP WOW". IF THIS CONDITION OCCURS WHILE DRIVING, CHECK THE WIRING OR WIRING CONNECTIONS FOR A LOOSE, PINCHED OR OPEN CONDITION.

INTERMITTENT FUEL GAUGE -

THERE HAVE BEEN SOME REPORTS OF INTERMITTENT FUEL GAUGES. THESE CONDITIONS HAVE BEEN CORRECTED IN PRODUCTION. IF YOU HAVE A CONDITION WITH ONLY THE FUEL GAUGE, THE CLUSTER IS SELDOM THE PROBLEM. CONTACT TECHNICAL ASSISTANCE FOR FURTHER INFORMATION.

SEPARATELY SERVICEABLE PARTS -

SEVERAL ITEMS CAN BE CORRECTED OR REPLACED WITHOUT REPLACING THE CLUSTER. THESE ARE:

1. THE VOLTMETER CAN BE CALIBRATED USING THE TECH 2.

2. IF PROBLEMS ARE FOUND WITH THE DASH LIGHTS, THE POWER INVERTER AND THE DIMMER SWITCH CAN BE REPLACED.

3. THE LENS IS AVAILABLE FOR REPLACEMENT.

4. A BULB PACKAGE IS AVAILABLE.

FIGURES: 00 ATTACHMENTS: 00

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.