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Pete
Pete, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 27537
Experience:  Over 15 years experience as a Mercedes dealer technician
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Mercedes-Benz E320 I am going to replace the Aux Battery in

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I am going to replace the Aux Battery in my 2006 Mercedes E320 CDI. Do I need a back up battery or any special instructions? The manual I have says only; Remove the neg terminal from the main battery then change out the aux battery.
Is this correct?
Hello,I will be glad to try and assist you with this,Welcome to Just Answer.

Hi.

Yes if you are replacing the auxiliary brake control battery under the hood then I would leave the key out of the vehicle,disconnect the negative cable from the main battery and then replace the small additional battery in the vehicle.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Customer: replied 5 years ago.
Pete you are calling this battery a brake control battery. This battery is located under the hood on the passanger side of the car. This battery has nothing to do with the instrumentation and will not mess them up?
Yes,this battery should be very small in size about the size of a lawnmower or motor cycle battery and is used only for the brake system as the brake system on this vehicle needs voltage to operate when or if the main battery fails this way you can still brake properly.

It is located under the dust filter housing on the passenger side under the hood up near the firewall.

This wont mess any instrumentation up.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
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