Lighting - Headlamp Beam Shakes/Vibrates
94 08 372017681/2
November 14, 2008.
Supersedes Technical Service Bulletin Group 94 number 08-09 dated June 2, 2008 for reasons listed below.
Affected Vehicles
94 Headlamp beam vibrates or shakes
Condition
- Headlight is vibrating or flickering. This condition is particularly noticeable at idle speed or when closing the front doors.
- The overall alignment and illumination is within vehicle specification.
Technical Background
Under certain operating conditions during idle speed, vibration and resonance may occur in the front of the vehicle, which may also stimulate the resonance frequency range of the headlight.
This is noticeable to the customer when the headlight beam flickers.
Production Solution
From MY 03, the idle speed for vehicles with 2.7 l and 3.0 l engines (automatic gearbox) was increased from 680 rpm to 740 rpm.
Service
1. Check the headlight securing points for correct seating.
2. Check the mounting of reflectors in headlights.
3. Install the headlight so that none of its parts touch the body.
4. Position the headlamps in the outer area of the wings with a rubber spacer as shown in Figure 1. Increase the tension between the wing bank and headlamps housing with a plastic wedge.
On 6 cylinder engines, the gradual increase of the idle speed up to max. 810 rpm can reduce the vibrations of the headlamps.
NOTE:
- The procedure above improves the complaint. Minor vibrations will still happen and are normal.
- Changes to the engine speed can only be made within the specified nominal engine speed range. (See data sheets in the workshop literature for exhaust emissions test for the relevant engine type.)
- Vehicles fitted with automatic gearboxes must not exhibit a tendency towards increased "creeping" due to the increased engine speed.
- The idling acoustics of the vehicle may be altered; check with customer if necessary.
- The headlamps must not be replaced under warranty. All headlamps have the same specifications.
Warranty
When procedure applies to vehicles under warranty, use the table.
Required Parts and Tools
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.