Battery Drain

[Brewmaster]

Sorry to say my first post is for help but I am hoping that someone on here might have the answer i am looking for. I own a 2004 E320 saloon and it has developed an electrical fault with the battery continually discharging. I have removed all fuses in engine bay,drivers cockpit and boot and still have a power draw of 5.7 amps. The Battery Control module in the boot has been tested and found to be OK. Thanks in advance for any advice.

 

[whitenemesis]

Not sure if the E class has a block heater, like the C class diesels? That can malfunction and basically short out. No fuse

 

[AMGeed]

A faulty door control module or seat controller could be the cause.
Have you checked the front and rear SAM's?
Have you got Comand? Often another cause for a draw when they don't shutdown.

Pinning down a current draw is time consuming and a real annoyance. I've been there.

One final thought, what current are you getting when the car is running? Should be 13.8v +. Oh, have you checked the condition of the aux battery in the engine bay? If that hasn't been chaged in a while that could be your problem.

 

[Major774]

5.7amps is massive, your battery would be dead in a few hours.

If all fuses are out then may be it's a large component not functioning (switching off).

 

[4life211]

You should check the alternator .The diode's block may be defective.A year ago I had the same defect as you ,but 3A drain.Replaced diodes, regulator and alternator bearings.

 

[Brewmaster]

Only 2 hours till dead. Now with the Garage causing some head scratching there now.

 

[Brewmaster]

Just to bring you up to date. The car is back from the Garage this morning after having a 5.7amps battery drain. After much testing nothing was found, new battery was fitted under warranty and battery drain went down to 0.2amp. No major drop in battery performance over the last 48 hours. Got to keep an eye on it and report back to garage if anything changes. Don't you just love ELECTRICKERY.