Mercedes-Benz W211 Battery Relay A 002 542 38 19 - Used Original Parts

Diagnosis and Common Symptoms

From the workshop floor, this relay is a frequent culprit behind one of the most common W211 electronic faults. A failure in this component disrupts the dual-battery charging system, leading to a persistent red "Visit Workshop!" warning with a battery icon on your instrument cluster. You will also likely see the "Convenience functions temporarily unavailable" message, as the system shuts down non-essential electronics to preserve starting power. In advanced stages of failure, this can lead to a drained main battery and a no-start condition. Fault codes stored in the Battery Control Module (BCM) will typically point towards an issue with the auxiliary battery circuit or charging system communication.

Introduction

Don't compromise your vehicle's sophisticated electrical system with unproven aftermarket electronics. This is a Genuine Mercedes-Benz battery relay, professionally salvaged and fully tested to ensure it performs to the original factory standard. We've bench-tested this specific unit for correct voltage switching and resistance, guaranteeing it's ready for installation. It is the reliable, cost-effective solution to restore proper function to your vehicle's power management system.

Product Details

• Brand: Mercedes-Benz
• Model Compatibility: W211 E-Class (E320, E350, E500, E55 AMG, etc.). Please verify part number A 002 542 38 19 matches your original unit.
• Part Name: Battery Isolation Relay / Auxiliary Battery Relay
• Condition: Genuine Used (Tested Working)
• Notes: This relay is typically located in the trunk area, mounted near the auxiliary battery. It is responsible for isolating the two batteries and managing the charging sequence.