Mercedes-Benz bulletin LI82.70-P-077433

Complaint During a phone call, the called party has difficulty understanding/cannot understand the driver, or interference/background noises are audible to the called party during a call. It becomes increasingly difficult to understand as the speed rises. Cause A. Seating of the microphones in the headliner. Side edges are covered by the textile cover (see picture "1") B. Assembly of microphones (B25/20 or B25/21) in the headliner. C. Dirt inside the microphone housing Remedy 1. Press finger on rear of microphone (on adhesive tape) 2. Remove microphone cap from the front 3. Eliminate protruding material residues of the microphone cutout at the headliner, e.g. with a soldering iron. The microphone must be seated in the headliner as shown in picture "2". 4. Push microphone from behind until it is firmly pressed into the headliner 5. Maintain pressure and press/clip cap into microphone from the front. Note: The cover cap must be clearly heard and felt to engage. 6. This procedure must be carried out on both microphones (B25/20 and B25/21) Note: • It is recommended to replace the cover caps. • The non-woven cloth in the cover cap protects the microphone from soiling and must not be removed. NOTE: The information contained in this document is intended for use by trained, professional technicians with the knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes resulting in the same or similar symptoms or conditions described in this document, and trained professional service technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained in this document does not guarantee warranty coverage nor does it extend the vehicle’s warranty in any way.

Owners of the 148 model years this bulletin names have filed 4,513 complaints with NHTSA since 2015. 931 of them name Electrical System — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.

On the 2020 Mercedes-Benz GLE-Class, the 13 owners who gave an odometer reading for Electrical System reported it at a median of 6,615 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.