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*Keyless Entry:* Without a proper auxiliary battery, you won't be able to conveniently unlock your E320 using the keyless entry feature during power disruptions
*Alarm System:* Your car's security system, including the burglar alarm, relies on the auxiliary battery to provide backup power and alert you and authorities of unauthorized tampering attempts even when the main battery loses power.***
*Clock Settings :* It assists in preserving clock and onboard computer memory, so they won't reset after main battery replacement or maintenance tasks involving power disconnection***
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Radio Presets and Personal Settings :* The presets for your audio system , as well as custom configuration and preferences made on the infotainment system , will be retained with help of auxiliary battery .
While you've listed numerous essential roles of the auxiliary battery in your 2003 Mercedes -Benz E320, keep in mind that the primary functionality might sometimes vary .For a definitive understanding of your specific ,vehicle reference to your owner's manual or seek advice from Mercedes dealers is advised as certain models or variations my possess difference setups.**
