2013 ML350 W166 - HELP! ACCIDENTALLY JUMP START MERCEDES WRONG POLARITY NOWWONT START
Thread Starter
Member
Joined: Nov 2017
Posts: 191
Likes: 107
From: Los Angeles
2001 E430, 2014 E 350, 2012 C63 PP30
2013 ML350 W166 - HELP! ACCIDENTALLY JUMP START MERCEDES WRONG POLARITY NOWWONT START
Guys,
I have a 2013 Mercedes ML350 W166. I accidentally connected the jumper cables incorrectly (from under the hood) after the battery needed some juice. I did not connect the jumper cables to the back battery (located under front passenger seat) but the red cross under the hood. I connected the ground to the red cross and the positive to the ground on the chassis.
Smoke was coming out of the alternator. When I hook up the car to jump start again the car does not start. I think i fried my alternator. What should I look for in diagnosing my issue?
The car seems to turn on accessories but does not wish to start.
Thank you for your time.
I have a 2013 Mercedes ML350 W166. I accidentally connected the jumper cables incorrectly (from under the hood) after the battery needed some juice. I did not connect the jumper cables to the back battery (located under front passenger seat) but the red cross under the hood. I connected the ground to the red cross and the positive to the ground on the chassis.
Smoke was coming out of the alternator. When I hook up the car to jump start again the car does not start. I think i fried my alternator. What should I look for in diagnosing my issue?
The car seems to turn on accessories but does not wish to start.
Thank you for your time.
Out Of Control!!
Joined: Apr 2019
Posts: 11,958
Likes: 6,802
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
$$ouch$$
Unfortunately there is no single protection against a polarity reversal.
Alternators use an AC/DC rectifier bridge built around 6 high Amp diodes plus a voltage controller. This is the prime candidate for any short-circuit.
1- Single out shorted circuits:
> Go ahead and disconnect ALT as well as 100% everything else directly at the PREFUSE power dispatch.
> Next reconnect one circuit at a time. The branches that feed shorted modules will draw high current.
2- Guess at non-responsive circuits:
> List SAM's fuses poped by shorted units. Exploded modules will remain silent
> Hook up a scanner to enumerate live modules. Trace circuits power with DVM.
Good luck for a low count of casualties
Alternators use an AC/DC rectifier bridge built around 6 high Amp diodes plus a voltage controller. This is the prime candidate for any short-circuit.
1- Single out shorted circuits:
> Go ahead and disconnect ALT as well as 100% everything else directly at the PREFUSE power dispatch.
> Next reconnect one circuit at a time. The branches that feed shorted modules will draw high current.
2- Guess at non-responsive circuits:
> List SAM's fuses poped by shorted units. Exploded modules will remain silent
> Hook up a scanner to enumerate live modules. Trace circuits power with DVM.
Good luck for a low count of casualties
Last edited by CaliBenzDriver; Feb 11, 2022 at 11:32 AM.
Out Of Control!!
Joined: Sep 2018
Posts: 14,678
Likes: 4,578
From: unbegrenzt
2017 GLE350 4MATIC
Guys,
I have a 2013 Mercedes ML350 W166. I accidentally connected the jumper cables incorrectly (from under the hood) after the battery needed some juice. I did not connect the jumper cables to the back battery (located under front passenger seat) but the red cross under the hood. I connected the ground to the red cross and the positive to the ground on the chassis.
Smoke was coming out of the alternator. When I hook up the car to jump start again the car does not start. I think i fried my alternator. What should I look for in diagnosing my issue?
The car seems to turn on accessories but does not wish to start.
Thank you for your time.
I have a 2013 Mercedes ML350 W166. I accidentally connected the jumper cables incorrectly (from under the hood) after the battery needed some juice. I did not connect the jumper cables to the back battery (located under front passenger seat) but the red cross under the hood. I connected the ground to the red cross and the positive to the ground on the chassis.
Smoke was coming out of the alternator. When I hook up the car to jump start again the car does not start. I think i fried my alternator. What should I look for in diagnosing my issue?
The car seems to turn on accessories but does not wish to start.
Thank you for your time.
Buy a scanner, read codes.
Carefully go through the fuse box in the engine bay and replace what needs replacing.
Clear codes.
Repeat the process over and over until you find the bigger problems like potentially fried alternator.
Check battery positive cable carefully.
Thread Starter
Member
Joined: Nov 2017
Posts: 191
Likes: 107
From: Los Angeles
2001 E430, 2014 E 350, 2012 C63 PP30
Unfortunately there is no single protection against a polarity reversal.
Alternators use an AC/DC rectifier bridge built around 6 high Amp diodes plus a voltage controller. This is the prime candidate for any short-circuit.
1- Single out shorted circuits:
> Go ahead and disconnect ALT as well as 100% everything else directly at the PREFUSE power dispatch.
> Next reconnect one circuit at a time. The branches that feed shorted modules will draw high current.
2- Guess at non-responsive circuits:
> List SAM's fuses poped by shorted units. Exploded modules will remain silent
> Hook up a scanner to enumerate live modules. Trace circuits power with DVM.
Good luck for a low count of casualties
Alternators use an AC/DC rectifier bridge built around 6 high Amp diodes plus a voltage controller. This is the prime candidate for any short-circuit.
1- Single out shorted circuits:
> Go ahead and disconnect ALT as well as 100% everything else directly at the PREFUSE power dispatch.
> Next reconnect one circuit at a time. The branches that feed shorted modules will draw high current.
2- Guess at non-responsive circuits:
> List SAM's fuses poped by shorted units. Exploded modules will remain silent
> Hook up a scanner to enumerate live modules. Trace circuits power with DVM.
Good luck for a low count of casualties
Out Of Control!!
Joined: Apr 2019
Posts: 11,958
Likes: 6,802
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
progressing...
Both SAM'S modules act as "Fuse holders & Pwr Mgr". They are located in:
- driver side engine bay (90% chance shot)
- passenger side trunk side liner (50% chance...)
Front SAM also controls the K57 main relay within PreFuse enclosure. It's a VIP computer acting as the ECU's butler for some peripherals... (Main Batt LIN Sensor)
Wiring diagrams are available in eBay shareware DVD or directly by online subscription sces (AllData, Mitchell,...)
Have a look at FCP Euro for sweet deals on your ALT & more...
🤞
Last edited by CaliBenzDriver; Feb 12, 2022 at 10:14 AM.
