Using W166 as Jump Donor Vehicle
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Super Member
Joined: Sep 2018
Posts: 706
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From: Los Angeles, CA
'22 GLE 350 | '15 ML250 | '87 560SL | '19 GLC 300 | '12 C250 (sold) | '02 ML500 | '98 C230
Using W166 as Jump Donor Vehicle
Hi guys --
I've now been in the same boat twice with my truck. Using the jump points in the engine bay (the red slider for the positive terminal, and the negative terminal ground point on the left side of the interior fender, I've failed miserably twice, jumping a car with a dead battery.
The first was my old W163, that sat for 2 weeks, had a pretty weakened battery, and after 5 minutes trickle charging from the W166, wouldn't start up. Took a good 30 minutes of trickle charging before the old truck would even attempt to turn over.
Today, my W204 had been sitting for 4 days, and was deader than dead (no unlock, lights etc.,), same thing. Sat for 20 minutes trickle charging, all the electronics lit up as soon as I connected the W166, but car refused to even try and turn over. Had to call AAA out.
Am I crazy, or are the W166's not meant to be jump donor vehicles due to the fact we're pulling the 12v from a line far from the battery, and not the battery itself?
No matter WHAT, the old ML500, if there was a car that needed a jump, you hook those big honkin' 2-gauge cables to that truck, whatever car was dead would light RIGHT up.
Some days I really miss the old girl...
I've now been in the same boat twice with my truck. Using the jump points in the engine bay (the red slider for the positive terminal, and the negative terminal ground point on the left side of the interior fender, I've failed miserably twice, jumping a car with a dead battery.
The first was my old W163, that sat for 2 weeks, had a pretty weakened battery, and after 5 minutes trickle charging from the W166, wouldn't start up. Took a good 30 minutes of trickle charging before the old truck would even attempt to turn over.
Today, my W204 had been sitting for 4 days, and was deader than dead (no unlock, lights etc.,), same thing. Sat for 20 minutes trickle charging, all the electronics lit up as soon as I connected the W166, but car refused to even try and turn over. Had to call AAA out.
Am I crazy, or are the W166's not meant to be jump donor vehicles due to the fact we're pulling the 12v from a line far from the battery, and not the battery itself?
No matter WHAT, the old ML500, if there was a car that needed a jump, you hook those big honkin' 2-gauge cables to that truck, whatever car was dead would light RIGHT up.
Some days I really miss the old girl...
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From: Montreal/Cape Coral FL
2012 X6 35i Sport, 2013 ML 350 BT, 2019 4Runner TRD Pro, 2020 CRV-AWD
Doesn't make sense. If the terminals are good enough as boosting points, then I'm guessing that maybe the connections on the dead car weren't solid.
Thread Starter
Super Member
Joined: Sep 2018
Posts: 706
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From: Los Angeles, CA
'22 GLE 350 | '15 ML250 | '87 560SL | '19 GLC 300 | '12 C250 (sold) | '02 ML500 | '98 C230
They were solid, trust me. Not the first time I've had to jump the W204. But had always done so with the W163 ML500. Gotta be something to jumping straight off of a battery, versus whatever is snaked up to that point in the engine bay.
Thread Starter
Super Member
Joined: Sep 2018
Posts: 706
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From: Los Angeles, CA
'22 GLE 350 | '15 ML250 | '87 560SL | '19 GLC 300 | '12 C250 (sold) | '02 ML500 | '98 C230
MBWorld Fanatic!
Joined: May 2017
Posts: 1,234
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From: Montreal/Cape Coral FL
2012 X6 35i Sport, 2013 ML 350 BT, 2019 4Runner TRD Pro, 2020 CRV-AWD
I'm tempted to do so, just to test your statement. Problem is, I'd need to run down a perfectly good battery to do so.
I have an idea. What if I was to put my battery load tester on the terminals and see if I get a big amperage draw?
I have an idea. What if I was to put my battery load tester on the terminals and see if I get a big amperage draw?
Thread Starter
Super Member
Joined: Sep 2018
Posts: 706
Likes: 114
From: Los Angeles, CA
'22 GLE 350 | '15 ML250 | '87 560SL | '19 GLC 300 | '12 C250 (sold) | '02 ML500 | '98 C230
Ooh good idea. You should be getting 12.8ish off the terminals in the engine bay, volt wise too, yes?
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2002 Ml320, 2012 ML350 & Slk55
My wife had to jump start our 166 when the battery was on its last legs.
Never done it before but she managed it with another lady in the dark from phone instructions.
They used the 166 jump points and it started up no problem.
To me that would suggest the jump points are up to the task.
If i had to jump start a car after sitting for 4 days I'd fix it properly.
Never done it before but she managed it with another lady in the dark from phone instructions.
They used the 166 jump points and it started up no problem.
To me that would suggest the jump points are up to the task.
If i had to jump start a car after sitting for 4 days I'd fix it properly.
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MBWorld Fanatic!
Joined: May 2017
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From: Montreal/Cape Coral FL
2012 X6 35i Sport, 2013 ML 350 BT, 2019 4Runner TRD Pro, 2020 CRV-AWD
I just put my load tester on the jumper points and it definitely put a load on the battery. Sucker was glowing. Voltage dropped to 12.39 right after the test and then slowly crept back up to 12.46.
