Audio System - AM Band Whining Noise When Braking
SI B 65 51 01Sound System, Cruise, Alarms, Monitors
November 2005
Technical Service
This Service Information bulletin supersedes S.I. B65 51 01 dated February 2001.
[NEW] designates changes to this revision
SUBJECT
Radio AM Band "Whine" from the Third Brake Light
MODEL
E53, X5 vehicles
SITUATION
Customer may complain of interference (oscillating whine noise) when tuning to certain weak-signal AM band stations (signal strength less then 9), and pressing the brake pedal.
CAUSE
Insufficient insulation of the third brake light.
CORRECTION
On a customer complaint basis only , provide shielding to the third brake light and its harness according to the procedure described below.
PROCEDURE
1. Remove five M10 screws (1, 3) securing the top portion of the rear hatch spoiler. Two of the screws (3) are accessible after removing the plastic covers (2).
2. Remove top cover of the hatch spoiler.
3. Remove two Torx T25 screws (4) securing the third brake light. Remove the third brake light (2) from the vehicle.
4. Remove two M10 (5) hex nuts securing the bottom part of the rear hatch spoiler.
5. Disconnect hose (1) at the windshield washer sprayer.
6. Remove AM antenna strip (3).
7. Produce shield grounding strap using:
^ two 12-10 AWG ring connectors
(OD=5/16", ID=1/4")
^ 20" piece of 12 AWG stranded insulated wire
8. Attach one end of the ground strap (1) to the bottom of the left hinge, as shown on the illustration.
9. Route the other end of the strap (1), through the opening of the windshield washer hose (2) into the hatch spoiler, up to the left mounting point (3) for the third brake light.
10. Reinstall the bottom part of the hatch spoiler.
11. Using aluminum tape (2), shield the housing of the third brake light (1) and the electrical harness (leaving the lens exposed). Also, in the same fashion insulate part of the electrical harness on the vehicle side.
12. Reinstall shielded third brake light (4).
13. Attach the grounding strap (2) to the left Torx screw (3) securing brake light (ground strap has to be in contact with aluminum shielding).
14. Install AM band antenna strip (1) in a new location: approximately 2" from the front edge of the spoiler (as shown on the illustration).
15. Reinstall top cover of the hatch spoiler.
PARTS INFORMATION
[NEW] WARRANTY INFORMATION
Covered under the terms of the BMW New Vehicle Limited Warranty.
Refer to KSD.