CL500, dead trunk battery,

jp*mc86

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Hi all, I can use your expertise. My CL 500 has a dead trunk mounted battery. I thought no problem, I tried to use my spare key to open lock. The lock will not turn rt/lt, so I figure there must be a jump start post somewhere in the engine compartment. I never found one, so I jacked up the front of the car. I figure I will go to the starter and attach a jumper cable to get power and then pop the trunk open. Problem is, the starter offers no room to connect a jumper cable. My next idea was to jack up the back of the car and see where the battery cable exits the trunk. No luck, can not detect cable exiting from trunk. Next idea was to check back seat for ski exit through middle of seat, no luck. I read on this forum using the cig lighter, except my ignition will not turn on without power, any ideas. Sorry, I forgot to mention that I disconnected negative battery post, was troubleshooting with hope that disconnecting neg post, reconnect would clear fault code. Trunk was closed before I re-connected negative battery post.


John
 
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robertjrt

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Hi all, I can use your expertise. My CL 500 has a dead trunk mounted battery. I thought no problem, I tried to use my spare key to open lock. The lock will not turn rt/lt, so I figure there must be a jump start post somewhere in the engine compartment. I never found one, so I jacked up the front of the car. I figure I will go to the starter and attach a jumper cable to get power and then pop the trunk open. Problem is, the starter offers no room to connect a jumper cable. My next idea was to jack up the back of the car and see where the battery cable exits the trunk. No luck, can not detect cable exiting from trunk. Next idea was to check back seat for ski exit through middle of seat, no luck. I read on this forum using the cig lighter, except my ignition will not turn on without power, any ideas.


John

Be very, very careful when you Jump start the battery, especially from another car.

Can you trickle charge the battery via the cigar lighter? It will take longer, but, probably safer.

Seek advice, the electronics are very susceptible to surge damage and if damaged will cost a lot of money to replace.
 

brandwooddixon

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Hmm, negative battery post disconnected?

There should be a positive jump start terminal under a black box within the engine compartment, there's usually an uncovered brass earth attachment post close by on the wing. Remember you're not trying to start the car only power it enough to open the boot.

If using the starter terminals then you'll need to hold the cables on manually and get another person to pop the boot.

If you have access to the car interior there are main battery cable junctions under the carpeting in the passenger footwell of the E-class, there may be some there on the CL as well.

The boot lock is probably siezed through lack of use. Liberal application of WD40 or Plus gas will free it eventually. Work the key gently so that you don't break it. Time and patience is needed though. When you finally get the boot open apply any oil with the boot open - this will allow the oil to penetrate further. There's an excellent DIY about boot locks.
 

television

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One way is to remove a number plate light and join a 12v source like a small battery charger to the live terminal on the light and turn on the side lamps, this will enable the remote to work
 

brandwooddixon

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That's a new one Malcolm.

Is it possible to remove those lights without going through the boot?
 

tromppost

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Your on the right track with the starter, the AA guy used a long bit of metel to get some juice to it so as he could use the key to remote open the boot.
The service guy at merc said they pull of the trim by the carpet and ""jump on the big red cable"" that runs to the battery in the boot, not much help to me!!
Hope you get it started, what a pain that there is not where under the bonnet to jump start it.
 

television

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That's a new one Malcolm.

Is it possible to remove those lights without going through the boot?

Yes they come off from the outside.


To get to the starter motor it is easiest by taking off the wheel arch liner
 
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J

jp*mc86

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Hi, I want to thank everyone who answered my post. I tried most of the ideas presented to me. The information provided about the heavy positive battery cable, under the passenger compartment floorboard was right on. I did apply power to the trunk lock using a battery charger, however it did not work. I swapped to a 12 volt battery, still did not work. I then searched the engine compartment near and around the fuse box. Never did locate a lug/terminal used for jump starting. Finally I called MB Road assistance, the tech went straight to the passenger floorboard and applied power, no luck. He then went to the rt rear fuse box and jumpered the central locking system, no luck. Using a jump box and jumper wire to a box under the rear seat, the trunk finally opened. He worked on the car for over three hours before getting the trunk to open. He even said there is no lug/terminal in the engine compartment for jump starting. All the ideas presented were viable and probably would have worked, if my battery negative lead was not disconnected in the trunk. Again, thanks for your input.
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Alex Crow

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odd that the passenger footwel terminal didn't work. i would also have tried here first, like your man.
 


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