baltos550

I have a 2009 S550 4matic and it has lost all power. Using the key to start the car, when it is turned to the "on" position, no lights on the dash turn on. The seats have no juice, the door locks do not work. The battery in the engine compartment is about 3 months old. Will have it towed to a shop, but any clues as to the cause?

Mike5215

Start with checking that the main battery terminals are tight. If you have a voltmeter check voltage at both batteries. I think the main battery resting should be around 14v.

BenzV12

As you have a sensible post now here is an insensible one for you to cheer up your mood

Jeremy Clarkson sucked all the power out of your battery because whenever he drives a car he loudly shouts powwwwweeeeeerrrrrrrr making all the power getting into the car he drives

DaveW68

It sounds to me like the accessory battery in your trunk is dead or completely drained as that controls everything in your car. The fact that it also won't turn over could mean that you alternator isn't making any power and may be kaput. It could also be something as simple as the voltage regulator being shot.

Mike5215

The best part about Thanksgiving is that there is no "wrong" time of the day to start smoking crack.

marthyh

Have you left the rear vanity mirrors in the roof open ?
Which would explain a flat accessoiry battery(in the trunk) so no powerlocks have experienced this on several occassions.
But then,when you use the key to enter the car, you would still be able to start..
Perhaps a main fuse blown ?

baltos550

Problem solved. A little embarrassing, the battery cable was loose. Thanks Mike5215. Always good to start with the basics.

Mike5215

Ha! I got one right. Glad that's all it was.