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Discussion Starter · #1 ·
My son's 1999 C230 Kompressor has been setting for quite a while.
His alternator went on the blink and he couldn't drive it, or get it fixed due to money.
He now needs to get it to a shop, but he cannot get in the trunk to jump start the car because of no power to the trunk due to dead battery.
And his regular type key only goes in half-way in the trunk key slot.

He can get in the car and get the hood open, but can't find any jumping terminals under the hood.

How do you get in to the trunk, or jump the car outside of the trunk in this situation???

Many thanks,
Steve
 

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1995 C220
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Its not obvious, but on drivers side, forward of the fuse panel on the left inner fender, but rearward of the hood seal, you should see a junction box that has about 2-3 ring terminals on it. You should be able to put your positive lead there. The negative lead can go anywhere that is bare metal on the chassis or engine, but there should be some ground leads that are nearby that you can hook to. They will have a stud sticking up and that stud will be welded directly to the inner fender, with multiple brown wires going to it. To be safe I just try to hook the negative to a bolt on the engine block somewhere.

You might get enough juice in it there to get the trunk popped, then I would give it a good charge directly at the battery terminals.
 

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Just looked at your link; it has a really good picture of the terminals I am talking about it. The picture shows it correctly. I'm not sure where he is getting that ground, but you can see in his picture, under the water bottle, there is a large nest of brown wires. The ground stud is under the water bottle attaching those wires together. The water bottle lifts up with a simple thumb screw.
 

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Discussion Starter · #6 ·
Battery pending...

georgebuhr and DRNewcomb
Sorry for my delay. Thanks very, very much for your replies. They were very helpful.
I hooked up my portable jump device / air compressor to the terminals under the hood and presto...popped the trunk open.
So our issue is whether the battery is permanently defective or is the alternator on the blink? I took the battery out of the car last night and tried charging it for about 8 hrs. on the 6 amp slow charger mode, and it never moved much.
BUT-I had the charger negative cable hooked to the neg. battery terminal, and not some other remote ground. Is that bad?
This whole thing started when the car will drive for a while, then the dash warning lights come on and it quit running on the road. When we hook up the portable jump device and leave it hooked up to the battery, the car will drive again; I just don't know how far it will drive with the jump device hooked to it.
I'm taking the battery to AutoZone today to have it analyzed. The car has 175k on the clock so I wouldn't be surprised if it is the alternator.
Question for anybody:
Is it critical for operation of this car for the battery to be fully operable?
Many thanks again!
 

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The alternator and battery are simple to test, you do not need anything fancy other than a simple basic analog multimeter, although if you can get it to a parts store, they have great tools for testing as well.

With a multimeter, and the ignition key off, positive lead on positive terminal of battery, negative to negative, you should get a reading of about 11.5 or more volts to the battery. If you get 10 volts or less, you have a bad cell in the battery and it needs replaced. Between that and 11.5, I would give the battery a really good charge and see if it holds it.

If you have 11.5 or more at the battery with engine off, you should be able to start the car. After its started, you should see at least 13.5 volts at the battery, this indicates that the alternator is charging it. If you need to jump start with your battery pack, you can do that and still test your alternator after you get it running. If you have 13.5 volts and it stays running, you most likely just need to replace the battery. How old is it, anyway?

Is it critical for battery to be operational? Odd question but the answer is, absolutely, unless you like to be stranded.

BTW, as far as hooking up connectors to battery, I'll give you a quick lesson. The reason why it is recommended not to connect a negative clamp to the battery direct is because there is a small risk of explosion. Battery emit an explosive gas, and when one has been sitting under the hood of a car, gotten hot, these gases can build up under there. Then when someone connect a positive then negative jump lead, this creates a spark that ignites the gas, causing the battery to explode. This is why they tell you when you are jump starting a car with jumper cables, to connect the positive leads to the battery first, then connect the negative leads to a ground that is away from the battery, like a bolt on the engine. This creates the spark in a location that is away from the battery and reduces the risk of explosion.

When installed correctly, our batteries have a vent tube that should be ran down to a hole that goes outside the car, reducing the amount of gases that build up in the trunk. Its always a good idea to make sure that this vent is connected.

If your battery isnt leaking acid and is generally clean and in good shape physically, this is not normally an issue unless you overcharge the battery, so I dont think its a big deal hooking it up the way you did. I've been hooking batteries up this way for decades and never had an issue. The only time I have ever had an issue is when I was bench charging a battery once and left the charger on over night. The next morning I had acid exploded all over the garage. Learned my lesson the hard way not to over charge a battery.

BTW if you ever see a battery leaking or looking wet on the outside, dont charge it, this is a good sign battery has an issue and charging it could cause an explosion.
 

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Discussion Starter · #8 ·
George,
Thanks for the excellent reply.
Well the battery didn't seem to take a charge, at least according to the volts/percentage gauge on the charger. It's a Mercedes battery, so it is at least 5 years old, from when he bought the car. There is a dark area around one of the ports on top of the battery {with the + (phillips)} on top. That can't be good.
So we'll see what AutoZone says, and I think I'll pick up a multimeter. It's crazy I don't have one anyway, with 5 BMW's and this car, lol. Eh???
I'll report back for the sake of anybody else that is benefiting from this.
Cheers.
 

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Discussion Starter · #9 ·
Took the battery to AutoZone and they put their tester on it.
It had 12.3 v or that's what I think I saw. He said that's not terrible, but he then ran the test.
He said that it will probably fail sooner than later. It looked like it was at about 75%. The alternator is most likely contributing to the weakness of the battery.
So it's just as expected.
Planning to charge it more this evening, then try to make it to the garage that is about 8 miles from here. It should be doable with the aid of the jump tool.
Thanks again. :surrender:
 

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Discussion Starter · #11 ·
Unfortunately I didn't have the the Benz there to check the alt. I only had the battery there to check.
My son is going to try to drive the car to a garage today and they will check the alt.
I was able to get a 100% charge in the battery last night. Hopefully it will take him the 8 miles or so, along with the fully charged jump device.
 

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faq section
 

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My '99 C230 had the voltage regulator go bad around 175K-Miles. Its about a $30 part and can be replaced fairly easily...without removing alternator form the car.

There are 2 different alternators for the car (alternators are interchangeable, but regulators are not) Bosch and a Valeo. Do a visual check before ordering. I had a supplier check by VIN and got it wrong.
 
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