Battery light in instrument cluster

Fred Owner/Technician California Posted   Latest   Edited  
2006 Mercedes-Benz E350 3.5L 7-spd (722.9) — WDBUF56JO6A820237
Code 9092 Auxiliary Battery

This has a new auxiliary battery, I have tested the auxiliary battery rely power in and out, activated the relay by hand and retested the power in and out, which proved the relay works perfectly, the battery control module does not ground the relay to activate it. I tested the powers and grounds at the battery control module in the trunk all powers and grounds tested good, I cleaned the connector with electrical cleaner spray, removed the battery control module and cleaned the mounting surface.

I also activated the relay from the trunk by grounding the wire to the relay and it activated.

We talked to the dealer they never sold a battery control module and a local Mercedes shop said he never seen one go bad.

This has no battery sensor on the negative cable only the battery control module mounted in the trunk 

Thanks for any assistance 


Nuno Technician

Could it possibly be you need to update the battery replacement with the scan tool. Program.

Ð Awarded
Fred Owner/Technician
Fred Resolution

We replaced the battery control module, problem solved, this requires no programming, build data is 05/05 from what I read the programming starts in 06 Thanks Fred

Resolution Ð Awarded