Navajo 2WD V6-4.0L OHV (1992)
Electronic Noise Suppressor: Customer Interest
Audio System - Whining/Buzzing Noise From Speakers
1991-2002 Navajo, B-Series, Tribute - WHINING BUZZING NOISE FROM RADIO SPEAKERS
This bulletin supersedes the following TSB(s): 09-015/01. Please update your records accordingly.
This bulletin supersedes 09-015/01, issued 12/21/01. The APPLICABLE MODEL(S)/VINs and PART(S) INFORMATION have been changed.
All 1991-94 Navajo
All 1994-02 B-Series (excludes all Flexible Fuel (FFV) B-3000).
A whining or buzzing noise can be heard coming from the audio system speakers. This may be caused by an electrical noise coming from the in-tank fuel
pump or its ground wire. A Radio Frequency Filter (RFI) is available to correct this concern. Customers having this concern should have their vehicle
repaired using the following procedure.
Do not perform the following procedure on FFV B-3000 vehicles, this procedure does not apply. To verify if vehicle is FFV, check 8th digit of
If 8th digit is V then vehicle is FFV.
If 8th digit is U then vehicle is not FFV.
Fuel pump audio noise is relatively constant and changes only slightly with engine RPMs. If the audio noise constantly changes with the engine
RPMs, the fuel pump is not the cause of the problem and the RFI filter will not effectively reduce the noise.
Customers having this concern should have their vehicle repaired using the following procedure.
Verify customer concern.
Turn the key to the "ACCESSORY" position and turn ON the audio unit, tune the radio to a station with clear reception.
Turn the ignition to the "RUN" position (do not start the engine).
The fuel pump should run for about 1 second with the key in the "RUN" position with the engine not running. Listen for electrical noise in
the speakers of the audio system.
If noise is present while the pump is running and stops when the pump stops, then the fuel pump is generating the noise. Proceed to
If noise is not present when the pump is running, or is constant even when the fuel pump quits running, then the noise source may not be
the fuel pump. Refer to PINPOINT TEST 2: NOISY RECEPTION of the applicable Workshop Manual for additional troubleshooting
and repair procedures.