Underhood Positive Battery terminal?

brian bray

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I was working on my '91 300 SL with the battery in the trunk disconnected so I could leave the doors open and not run the battery down. I walked by and shut the trunk without thinking. Does this car have an engine compartment easy to reach positive terminal that I can hook to? If so, where is it? Thanks in advance. Brian Bray
 

AMGeed

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Does your key not open the boot?

Sorry, can't help with any positive terminal inside the engine compartment.
 
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brian bray

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Does your key not open the boot?

Sorry, can't help with any positive terminal inside the engine compartment.


The key does not directly unlatch the trunk. The release is done electrically. Thanks for your reply though.
 

sturge

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I thought there would be access via a key. What happens if the battery goes flat?
 
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brian bray

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I thought there would be access via a key. What happens if the battery goes flat?

Most cars have an positive terminal in the engine compartment for just that reason. You can either attach jumper cables or even a small battery charger since you don't need that much juice to open the trunk. I just don't know the location of the positive terminal in the engine compartment. Help!
 
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brian bray

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Most cars have an positive terminal in the engine compartment for just that reason. You can either attach jumper cables or even a small battery charger since you don't need that much juice to open the trunk. I just don't know the location of the positive terminal in the engine compartment. Help!
 

Auto Addict

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You could try connecting to the positive of the starter motor.
 
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brian bray

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You could try connecting to the positive of the starter motor.

Thanks. I know I can connect to the positive on the starter or the alternator; I just assume there is a stand alone positive terminal for that purpose in the engine compartment. The car is in my garage and is not a daily driver so this is not an emergency or critical situation but is a recent purchase and I like to learn everything I can with a new acquisition. Thanks for your help.
 
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brian bray

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Thanks. I know I can connect to the positive on the starter or the alternator; I just assume there is a stand alone positive terminal for that purpose in the engine compartment. The car is in my garage and is not a daily driver so this is not an emergency or critical situation but is a recent purchase and I like to learn everything I can with a new acquisition. Thanks for your help.

Problem Solved! Thanks to all who responded. My wife (not a car person!) suggested that I get online and describe the problem. I did and there were several suggestions. I tried the first and it worked.
Here is the solution:
1) insert the key into the trunk lock;
2) turn the key to the left;
3) wait 10 seconds;
4) turn the key back;
5) push in and the trunk releases

Brian Bray
 

andynpz

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Brian, there is a stand alone Negative terminal under the bonnet of many Mercs. Not a positive though as this would be a considerable hazard when using tools, which would weld themselves to the engine if they accidentally touched the positive simultaneously! And burn your hand!! And flatten your battery !!!

Good on you for publishing the right way to do it - interesting
 

EmilysDad

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Brian, there is a stand alone Negative terminal under the bonnet of many Mercs. Not a positive though as this would be a considerable hazard when using tools, which would weld themselves to the engine if they accidentally touched the positive simultaneously! And burn your hand!! And flatten your battery !!!

Good on you for publishing the right way to do it - interesting

Mine has a positive terminal under the bonnet like many other Mercs where the battery is elsewhere ...... it's insulated with a red plastic cover.
 

EmilysDad

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Problem Solved! Thanks to all who responded. My wife (not a car person!) suggested that I get online and describe the problem. I did and there were several suggestions. I tried the first and it worked.
Here is the solution:
1) insert the key into the trunk lock;
2) turn the key to the left;
3) wait 10 seconds;
4) turn the key back;
5) push in and the trunk releases

Brian Bray

So you can open the boot with the key .... :rolleyes:
 

flowrider

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Brian, there is a stand alone Negative terminal under the bonnet of many Mercs. Not a positive though as this would be a considerable hazard when using tools, which would weld themselves to the engine if they accidentally touched the positive simultaneously! And burn your hand!! And flatten your battery !!!

Good on you for publishing the right way to do it - interesting
Both my previous MB's had a positive terminal in the engine bay underneath a plastic cover.
 
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brian bray

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Brian, there is a stand alone Negative terminal under the bonnet of many Mercs. Not a positive though as this would be a considerable hazard when using tools, which would weld themselves to the engine if they accidentally touched the positive simultaneously! And burn your hand!! And flatten your battery !!!

Good on you for publishing the right way to do it - interesting

It worked but I really don't understand why it worked. Consider:
1) if the battery is disconnected, there is no juice anywhere;
2) the key goes in on the far right side but the trunk lock is in the middle;
3) If there is no juice, the 10 second wait is meaningless; if there is a mechanical connection between the key and the lock (i.e. a rod); again, the 10 second wait is meaningless.
Only the "SHADOW" knows, unless someone has a better explanation!

Brian Bray
 

EmilysDad

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It worked but I really don't understand why it worked. Consider:
1) if the battery is disconnected, there is no juice anywhere;
2) the key goes in on the far right side but the trunk lock is in the middle;
3) If there is no juice, the 10 second wait is meaningless; if there is a mechanical connection between the key and the lock (i.e. a rod); again, the 10 second wait is meaningless.
Only the "SHADOW" knows, unless someone has a better explanation!

Brian Bray

I've no idea about the 10 sec wait, but it does stand to reason that there's a mechanical connection between the key & the lock for exactly the situation you've just found yourself in ..... a flat battery.
 

Flyinspanner

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You can probably do it without the wait.
It’s just a boot lock, turn, centre, and push.
 

andynpz

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Both my previous MB's had a positive terminal in the engine bay underneath a plastic cover.

Oh dear! Forgive my ignorance please - I wish I'd thought about it a bit more before I wrote :oops:
 

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