REDUCED FM RADIO RECEPTION (INSTALL GROUND PLANE KIT). Chevrolet Corvette 1990

SUBJECT: REDUCED FM RADIO RECEPTION (INSTALL GROUND PLANE KIT)

MODELS: 1988-91 CHEVROLET CORVETTE

CONDITION:

SOME OWNERS MAY EXPERIENCE LOWER THAN EXPECTED RADIO RECEPTION ON THE FM BAND ONLY.

CAUSE:

THE ANTENNA LACKS A PROPER GROUND PLANE TO INSURE ADEQUATE RADIO RECEPTION. THIS GROUND PLANE WAS ADDED IN PRODUCTION AT THE START OF THE 1992 MODEL YEAR.

CORRECTION:

A GROUND PLANE KIT, P/N 10246147, HAS BEEN RELEASED TO ADD A GROUND PLANE FOR THE ANTENNA AND INSURE THAT THE ANTENNA GROUNDS ARE ADEQUATE. IT IS IMPORTANT TO FIRST CHECK FOR OTHER CAUSES OF POOR RECEPTION, SINCE THE KIT WILL NOT IMPROVE RECEPTION IF OTHER CONDITIONS CAUSING POOR RECEPTION EXIST. MAKE THE FOLLOWING CHECKS FIRST, BEFORE INSTALLING THE KIT:

1. TURN THE RADIO ON AND CHECK THAT THE ANTENNA MAST IS FULLY EXTENDED. CLEAN THE MAST, THEN RETRACT AND EXTEND THE MAST AND CLEAN IT AGAIN, FOLLOWING THE INSTRUCTIONS IN THE OWNER'S MANUAL.

MEASURE THE RESISTANCE OF THE FULLY EXTENDED MAST FROM THE TOP OF THE ANTENNA TO THE BOTTOM OF THE LOWEST SECTION. IF THE RESISTANCE IS MORE THAN 2 OHMS, REPLACING THE MAST MAY IMPROVE RECEPTION, ESPECIALLY IF FLEXING THE MAST CAUSES LARGE RESISTANCE CHANGES.

2. MAKE SURE THAT THE ANTENNA GROUNDS ARE CLEAN AND TIGHT.

3. FOLLOW THE DIAGNOSTICS IN THE SERVICE MANUAL FOR POOR RECEPTION.

IF THE ABOVE STEPS DO NOT IMPROVE THE RECEPTION, INSTALL THE KIT ABOVE. COMPLETE INSTRUCTIONS ARE INCLUDED WITH THE KIT.

PART AVAILABILITY:

PARTS ARE EXPECTED TO BE AVAILABLE BY 10/25/93.

WARRANTY INFORMATION:

LABOR OPERATION: T3399 LABOR TIME: 1.5 HRS.

FIGURES: 0

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.