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Battery dead can’t unlock it. Can’t get to the battery as…

Customer Question
Battery dead can’t unlock...

Battery dead can’t unlock it

Mechanic's Assistant: Did you test the battery with a voltmeter? And have you ever changed one before?

Can’t get to the battery as the car is locked

Mechanic's Assistant: What is the model/year of your Mercedes?

2005 SL500

Mechanic's Assistant: Are you fixing your SL500 yourself? What have you tried so far?

Tried the manual key but door won’t unlock.

Submitted: 8 months ago.Category: Mercedes
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Answered in 4 minutes by:
11/15/2017
Mercedes Mechanic: Matt, Engineer replied 8 months ago
Matt
Matt, Engineer
Category: Mercedes
Satisfied Customers: 23,326
Experience: Mechanical Engineer with 23 years experience in the auto industry, 8 yrs in formula 1 engine testing
Verified

Hello

A flat battery means you can't get the deadlock or alarm system to release its grip

I'd start by charging the battery you should be able to do this via the cigarette lighter / accessory socket. You'll need the appropriate attachment for your charger but car accessory shops sell these- Alternatively if you can't get into the car/ boot the other way to do this is jack the car up so you can get under the front.

Locate the starter motor and the large power cable that runs to it - connect the positive battery charger lead to this terminal

then connect the charger negative lead to the metal of the engine block

This should complete the charging circuit and get some power into the battery allowing you into the car

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Mercedes Mechanic: Lou P. master tech, Mercedes Technician replied 8 months ago
Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 6,103
Experience: 20 years Master Certified excellent fix rate and have access to factory wiring, and instructions.
Verified
Hello, lou here , here is how you can get into the trunk to charge the battery. Its a video i madehttps://youtu.be/cG7q5BlEBfMThis will allow you to get to the main battery and charge it to be able to unlock the doors . Hope this helps. Please take a second and click the stars at the top of the screen to rate my service so I may receive my credit for helping, 5 STARS is ideal. Please request me in the future! Keep in mind that when you rate it does NOT end our conversation, you can still return here to me for follow up information if needed just simply reply back, THANKS! Lou P Master Mercedes-Benz Tech Master ASE Certified
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