Autopsy: Infamous "Y" cable from alternator to starter to battery

[Deancm]

I have a NCV3 2500 3L V6 built June 2008. As preventive maintenance I replaced the infamous "Y" Cable. Attached are photos of the old cable and one of the newly installed cable.

1. Shows the 300 Amp fuse shrink wrap cut open. There is a serious design problem here. Note where my fingers are holding the shrink wrap open around the corrugated outer covering. This allows the corrugated covering to be channel for any water entering any break in this outer covering to flow down to the fuse which is the low point of the installation. The cable is just crimped and not soldered to the fuse.

2. Shows the 300 Amp fuse split open. The fuse is a narrowed part of the brass piece crimped around the cable at each end. It has plastic molded around it. But note, I am holding the part that goes in the center that says "300 A". This insert (which in the picture is split) is just clipped in, so it is not sealed. This allows water to corrode the fuse. Plus heat from current flow does not help.

3. The "Y" part of the cable split open looks good. It was soldered as well as crimped.

4. This is the tag for the old cable showing it was built May 22, 2008.

5. Here is the new cable installed. Note the heat shrink is over the cable and NOT the corrugated covering. BIG IMPROVEMENT!

 

[3mbusa]

Dean,

We have a 2012 MB 3500, I don't know if we have the revised cable or not? That said, do you know of any preventive measures that can be applied to the cable to correct the problem?

 

[Walter Clark]

I have a '12 2500 Crew. It has the Y cable with the shrink stopping before the split loom, like what Deancm described as "new".

If one had the earlier style where the shrink extends onto the split loom and it has not yet gone bad on them, it should be possible to cut the shrink around the cable where it begins to cover the split loom, slide the loom back a bit from each end of the remaining shrink tube, then wrap the ends of the remaining shrink tube with a self-amalgamating (or self-fusing) electrical repair tape. That wont remove any contamination or moisture already in the fuse area, but it should stop it from getting worse. It think it might be a good idea to warm the area covered by the exiting shrink tube with a hair dryer or heat gun to drive out any moisture before doing the added wrap.

If uncertain whether the joints are already corroded and need replacing or not one could remove all the shrink tube and after determining it is not bad an not wet, wrap the whole thing with self-fusing tape.

A good product that will work above any temps likely to be found in the engine compartment is Scotch® Self-Fusing Silicone Rubber Electrical Tape 70. Note that some products labeled as self-fusing are not rated to work over 200F, and some non-brand named products dont always fuse properly.

 

[sajohnson]

Dean,

Excellent post! Thank you for taking the time to do that -- it will help a lot of people.

The Y cable on our 2008 cab-chassis (2009 Winnebgo View) went bad a while back. The first clue I had was the Scangauge showing less than ~14.0 to 14.1V. Also, the coach batteries were not being charged.

I'd read about the problem and was almost certain it was the cable, but just to confirm it I performed a 'stress test'. We have a large whole house inverter, so I used it as a load. With the engine running, we plugged in a toaster and turned it on. As you'd expect with a cable with resistive connections there was serious voltage drop. Then I had the bright idea to touch the cable at various points to see where is was warm. Despite the connection at the starter lug being soldered, it turned out to be the hottest -- hot enough to leave a blister on my finger. D'oh! An IR thermometer would have come in handy there.

I still have the old OE cable. You've motivated me to cut it open and see how it looks.

I have to say that I'm disappointed with MB. This is clearly a design flaw. It is not something the owner/driver could damage due to abuse. It is obvious that the MB engineers made a mistake. MB should step up, do the right thing, and issue a "customer satisfaction campaign" (or whatever euphemism they prefer) and replace the remaining Y cables, as well as reimburse those who have already replaced it.

Part of the problem for those of us with a "Dodge" van or cab-chassis is that we're stuck in the middle -- Dodge doesn't work on Sprinters anymore, and MB says, "It's a Dodge, call them".

That issue aside, I'm not aware of any Freightliner or MB Sprinter owners who have had the Y cable replaced free of charge either.

A defective cable like this is inexcuseable from any mfr, but especially MB. They should be embarrassed, and bending over backwards to fix something like this, but instead they give customers the stiff arm.

I just had our View aligned at the local MB dealer on Thursday. They are already sending me auto-generated emails asking me to trade in my "2008 Sprinter" on a shiny new MB vehicle. Based on how they have responded to this faulty Y cable issue, I can't say I'm overly excited about the idea of buying one of their cars.

Once again, thanks for a great post.

 

[rb3232]

Dean,

We have a 2012 MB 3500, I don't know if we have the revised cable or not? That said, do you know of any preventive measures that can be applied to the cable to correct the problem?

You might consider soldering all connections on your cable. (Use lots of flux so the solder flows deeply)

I even cut the insulation back (out) from under the fuse support crimps and recrimped them on to the conductor and soldered them too. Then I wrapped the whole area including the fuse with Rescue tape. The tapes fuses together very quickly. (Silicone tape?)

 

[rb3232]

I have a NCV3 2500 3L V6 built June 2008. As preventive maintenance I replaced the infamous "Y" Cable. Attached are photos of the old cable and one of the newly installed cable.

1. Shows the 300 Amp fuse shrink wrap cut open. There is a serious design problem here. Note where my fingers are holding the shrink wrap open around the corrugated outer covering. This allows the corrugated covering to be channel for any water entering any break in this outer covering to flow down to the fuse which is the low point of the installation. The cable is just crimped and not soldered to the fuse.

2. Shows the 300 Amp fuse split open. The fuse is a narrowed part of the brass piece crimped around the cable at each end. It has plastic molded around it. But note, I am holding the part that goes in the center that says "300 A". This insert (which in the picture is split) is just clipped in, so it is not sealed. This allows water to corrode the fuse. Plus heat from current flow does not help.

3. The "Y" part of the cable split open looks good. It was soldered as well as crimped.

4. This is the tag for the old cable showing it was built May 22, 2008.

5. Here is the new cable installed. Note the heat shrink is over the cable and NOT the corrugated covering. BIG IMPROVEMENT!

I guess the first cable fix MB did was solder the the Y joint. I'm sure on my 2007 the Y joint was only crimped. (Until I soldered it.)

 

[dave61]

I have a NCV3 2500 3L V6 built June 2008. As preventive maintenance I replaced the infamous "Y" Cable. Attached are photos of the old cable and one of the newly installed cable.

1. Shows the 300 Amp fuse shrink wrap cut open. There is a serious design problem here. Note where my fingers are holding the shrink wrap open around the corrugated outer covering. This allows the corrugated covering to be channel for any water entering any break in this outer covering to flow down to the fuse which is the low point of the installation. The cable is just crimped and not soldered to the fuse.

2. Shows the 300 Amp fuse split open. The fuse is a narrowed part of the brass piece crimped around the cable at each end. It has plastic molded around it. But note, I am holding the part that goes in the center that says "300 A". This insert (which in the picture is split) is just clipped in, so it is not sealed. This allows water to corrode the fuse. Plus heat from current flow does not help.



3. The "Y" part of the cable split open looks good. It was soldered as well as crimped.

4. This is the tag for the old cable showing it was built May 22, 2008.

5. Here is the new cable installed. Note the heat shrink is over the cable and NOT the corrugated covering. BIG IMPROVEMENT!

Where is this "Y" cable located on my 2008 Dodge/Sprinter 3500 diesel...? Looks like the oil sump area under the carriage, but I'm sitting in my underwear right now and drinking a cup of joe. All kidding aside, I'll get dressed and scope it out because another poster recommended I check this for my electrical issues... Hard to believe Dodge wouldn't have checked this notorious "Y" cable out last year, but considering everything I've experienced with Dodge it probably is the source of ALL my problems after driving through "wet Alaska" two years ago.

AMEN...

I will report back my findings so others can solve this problem..!

 

[dave61]

Located "Y" connector and see that it's a tough area to get to and replace... the shrink tubing looks ok, but I'll need to cut it open to get inside and see if there is any corrosion. Checked my maintenance/repair records and the "Y" connector wasn't touched during all of the repairs... not to say it wasn't looked at, but not replaced.

The ECM was replaced (not the CPU... which is a different acronym for similar components)

 

[sajohnson]

Located "Y" connector and see that it's a tough area to get to and replace... the shrink tubing looks ok, but I'll need to cut it open to get inside and see if there is any corrosion. Checked my maintenance/repair records and the "Y" connector wasn't touched during all of the repairs... not to say it wasn't looked at, but not replaced.

The ECM was replaced (not the CPU... which is a different acronym for similar components)

You might consider replacing it regardless of what you find.

The cable was not designed well. It seems to be a case of not 'if' it will fail but when.

An ethical mfr would step up, acknowledge their mistake, and replace the cable free of charge (or reimburse owners who have already had it replaced).

 

[lindenengineering]

You might consider replacing it regardless of what you find.

The cable was not designed well. It seems to be a case of not 'if' it will fail but when.

An ethical mfr would step up, acknowledge their mistake, and replace the cable free of charge (or reimburse owners who have already had it replaced).

WhaoH Guys
Hold on a moment!
This main battery charge cable is not unique to the 906 Sprinter.
Quite a few MB car lines have it installed as well.
Another car that comes instantly to mind is the c230 Kompressor.
Like this little bugger :-
https://www.google.com/?gws_rd=ssl#q=2003+c230+compressor+pictures
Now the resistor unit is located on top of the bell housing and the body. Hidden but gives the same problems and not so nice to remove--It takes out the alternator and charging module when it shorts down! Not like a Sprinter!

Now its clearly an engineering policy from MB to site the device in the main battery cable.
I think its a waste of time but clearly they don't.
Likewise I consider the use of twisted pairs in German car harnesses to be waste of time and "old fashioned" when the Anglo/American/ Japanese method is screening. But they use it and for reasons best known to themselves continue to do so.

In this auto repair business we Pros in the business get to know the strengths and weaknesses of the brands we work on. Just because it has an MB badge on the front don't for one minute think that this piece of bent iron is any different! Its not!

Every manufacturer has recommended PM programs at mileage intervals.
MB at 80,000 miles suggest a check of all electrical harnesses etc. That doesn't mean a cursory look over but an in depth inspection and replace where necessary.

Landrover has similar recommendations like the serp belt tensioner and a very involved service read expensive!
Even Toyota recommends changing the Hybrid coolant pump at 100, 000 miles to prevent converter Hybrid system overheat, and prompting an abrupt shut down in the road!

In fact if you could look now at an Indentifix rogues a gallery of brands and certain mileages you will be amazed at what fails regularly.

This Y cable is just one small irritation and it has been upgraded a few times. BUT MB in this case will not reimburse anyone I am sure, it is regarded as a service item!
If that's OK with you chaps:
Dennis

 

[dave61]

My thoughts are to solder the connections and do a voltage drop test across all points to make sure there is no hidden corrosion within the cable itself before I buy a new one.

 

[smiller]

My thoughts are to solder the connections and do a voltage drop test across all points to make sure there is no hidden corrosion within the cable itself before I buy a new one.

That would normally be the way I would look at it as well, but given how common the problem is with the early NC3V models and that the current upgraded part can be had for only $70 or so my choice was to just get under the vehicle once and be done with it.

 

[wmlog]

Excellent evaluation! How many Sprinters were manufactured with this inherently faulty cable installed? How is it that MB has remained silent on this for so long?

Here are photos of the damaged insulation on a 2008 Sprinter, with temporary repairs.

For anyone with any doubts about the criticality of this fault, the exposed ends of the fuse are directly from the alternator output and the main (start) battery! All other metal in the area is ground!

 

[sajohnson]

[/B]

WhaoH Guys
Hold on a moment!
This main battery charge cable is not unique to the 906 Sprinter.
Quite a few MB car lines have it installed as well.
Another car that comes instantly to mind is the c230 Kompressor.
Like this little bugger :-
https://www.google.com/?gws_rd=ssl#q=2003+c230+compressor+pictures
Now the resistor unit is located on top of the bell housing and the body. Hidden but gives the same problems and not so nice to remove--It takes out the alternator and charging module when it shorts down! Not like a Sprinter!

Now its clearly an engineering policy from MB to site the device in the main battery cable.
I think its a waste of time but clearly they don't.
Likewise I consider the use of twisted pairs in German car harnesses to be waste of time and "old fashioned" when the Anglo/American/ Japanese method is screening. But they use it and for reasons best known to themselves continue to do so.

In this auto repair business we Pros in the business get to know the strengths and weaknesses of the brands we work on. Just because it has an MB badge on the front don't for one minute think that this piece of bent iron is any different! Its not!

Every manufacturer has recommended PM programs at mileage intervals.
MB at 80,000 miles suggest a check of all electrical harnesses etc. That doesn't mean a cursory look over but an in depth inspection and replace where necessary.

Landrover has similar recommendations like the serp belt tensioner and a very involved service read expensive!
Even Toyota recommends changing the Hybrid coolant pump at 100, 000 miles to prevent converter Hybrid system overheat, and prompting an abrupt shut down in the road!

In fact if you could look now at an Indentifix rogues a gallery of brands and certain mileages you will be amazed at what fails regularly.

This Y cable is just one small irritation and it has been upgraded a few times. BUT MB in this case will not reimburse anyone I am sure, it is regarded as a service item!
If that's OK with you chaps:
Dennis

There are 80 and 90 year old cars that still have their original battery cables.

MB can claim anything they want, we all know that a battery cable is not a wear/service item!

All of our cars (14 to 22 years old) have their OE cables. Even my '67 Camaro has the cables it rolled out of the factory with.

It's absurd (and insulting) for MB to claim that battery cables are a "service item". In which universe? Barring some catastrophic meltdown, battery cables should last the life of the vehicle.

The older style lead battery cable terminals sometimes have to be replaced, but rarely the cable itself. Most newer cars have steel terminals on the cables, which last longer. Corrosion isn't the problem it used to be.

People understand that many parts wear out after a reasonable number of hours or miles. That's expected for a variety of items, including motors; pumps; clutches; bearings; brakes; belts; tires; hoses, etc. Even engines and transmissions may eventually have to be rebuilt or replaced -- but a battery cable?

Nothing's perfect. Some parts fail prematurely. Hopefully under warranty. If not, an if the failure is due to a design/engineering error (not abuse) an ethical company that cares about getting repeat customers will step up, admit their mistake, and fix the problem free of charge.

I am under no delusion that MB is going to do the right thing here. After all, they don't have to. The NHTSA isn't forcing them. Covering the cost of replacing the battery cables that were poorly designed by their own engineers would cut into this quarter's profit. Never mind the incredible goodwill it would generate, and the increase in future sales. Nope, that doesn't matter. All that matters is the present.

It's actually really sad. MB used to be #1 in the world for reliability. They traded with Toyota for first and second place. Now they are toward the bottom of the barrel. In the April Auto Issue of CR, MB is #21 out of 28, based on their reliability and the road tests. Only 20% of their vehicles are "recommended" -- just 1 in 5. The average road test score for MB cars is very high -- one of the best -- they are just very unreliable. MB has 2 of 15 cars in the list of the absolute least reliable production cars in the world.

I guess this Y cable issue should not be surprising. What does surprise me is the big stiff arm from MB.

 

[lindenengineering]

Wow!
Comparing a mid last century vehicle to one of today.
Its like comprising a "charlie choo" steam engine with the French TGV!

I see the Camaro mentioned!
Hmm! 450 CCa battery , tiny 35 amp alternator or dynamo and no modules unless you count the spark module on top of the Delco, wiring harness weighing about 50 lbs tops simple positive switch switches, no need for a Can Bus indeed not a lot of need for anything else it was all basically manually operated.

OK let leave museum pieces behind because they have no relevance and get into this century after all its now 2015 AND there's no going back!
A Sprinter or any modern car!

A 900 cca battery, a small starter motor that punches out huge amounts of power to start your your stinking little diesel engine in few seconds or so crank of cranking. An alternator punching out say 100 amps, about 250 lbs of harness and at last 15 modules all attached it. (Some cars have as much as 52 modules in them)
Gizmos can't forget gizmos, systems, infotainment, telematics, butt heating, split system A/C well the list goes on doesn't it! With us all riding along on the Can-bus otherwise the harness would be about a 1000 lbs I daresay.
Simply put today's car's have to run within a tight voltage parameter of around 13.3 to 14.2 volts. The main circuits include the battery cable are subjected to a huge amount of current flow and in time degrade.

Now at the pointed end of getting grubby in the shop, battery cables get replaced more often than you might imagine! (unless you do this sort of work for a living/profession.)
Its not absurd on the contrary only bringing last century thinking into the argument is

And by the way going and buying some aftermarket parts can end up as being very expensive experience if its not to as spec! That is how crucial some of this stuff is these days.

What I think is questionable is/are German auto industry approaches to some things but putting a protection device in the main charge cable is a propensity not seen on other American/Asian brands for the most part.
You can be rest assured that some chief engineer has deemed it necessary and it is adhered to and regarded as a consumable. A lot of this stuff is to be tossed out at 100,000 miles.
Dennis

 

[Rensho]

Took a peek under my 2014 I4 and the cable seems to be a straight cable going into the Y. No sign of any fuse.

 

[lindenengineering]

Took a peek under my 2014 I4 and the cable seems to be a straight cable going into the Y. No sign of any fuse.

Rensho
Now we are talking about a different animal. In my lesser being opinion a far better van!
For me this is a sweety and clearly MB spenty some time on this 'un before they launched it!
My choice for a commercial van any time.
Dennis

 

[Landyacht]

Adding my Y cable experience to the KB.

After many weird CEL issues that seemed to point to a low voltage gremlin I pulled my Y cable w a mfg date of 5/07 off of my '08 MB 3500 NCV3 and found it in perfect shape. The heat shrink over the fuse was NOT installed over the sleeve material and seemed to be assembled as per spec. Rather than perpetuate the nonsense I just put in a new MB cable since I was under the truck already. Sadly it was not the issue causing my mysteriously numerous yet separate CEL issues.

Ahh the joys of electronical sensor wonderment combined with proprietary MB software. My frustrating search continues as I start to envy the simplicity and reliability of the Beverly Hillbillies simple truck..... sorta.

Mike

 

[RonR]

Dennis
I have to disagree with some of your comments.
While it may be that the battery voltage spec is 13.3 to 14.2, is could easily have been designed to work with 10 to 24V. From the got to get home minimum to the dumb ass winter 24V jump start. It may have cost a dollar or two more but with todays silicon it is just not a big deal to work over a wide input voltage range. Working at the extremes indicates a problem, so every warning on the dash should be flashing but think how happy you would be to go that last 20 miles to a paved road.
Using #2 cable with a 220A alternator is marginal. At full load this drops about a third of a volt to the main battery (not counting any drop in the ground cable).
A non-serviceable hard to examine inline fuse is just asking for trouble.
A single ground strap is also just cheap and asking for trouble.
Ron

 

[lindenengineering]

Dennis
I have to disagree with some of your comments.
While it may be that the battery voltage spec is 13.3 to 14.2, is could easily have been designed to work with 10 to 24V. From the got to get home minimum to the dumb ass winter 24V jump start. It may have cost a dollar or two more but with todays silicon it is just not a big deal to work over a wide input voltage range. Working at the extremes indicates a problem, so every warning on the dash should be flashing but think how happy you would be to go that last 20 miles to a paved road.
Using #2 cable with a 220A alternator is marginal. At full load this drops about a third of a volt to the main battery (not counting any drop in the ground cable).
A non-serviceable hard to examine inline fuse is just asking for trouble.
A single ground strap is also just cheap and asking for trouble.
Ron

Ron
Personally I agree with you !
BUT
I am not in charge of specs at MB!
Having worked for several manufacturers I can understand the philosophy of the Chief Engineer and the hand me down of policy.

In short do NOT question the Chief Engineer or his Engineering commitee (in this case the Herr Doktor Whatisface.) Unless you want to suffer the wrath of the Senior Engineering Div!
One of my collegues was severely reprimanded for questioning engineering policy on a big truck --It wasnt pleasant! He was frimly put in his place publically in the factory and he almost lost his job!

Plus the mantra I spout on this forum which has been said & oft stated ! Quote
"What works well here will work in Yankee land"!
Tell those snivelling Yanks to live with it!

If it doesn't, try getting a change at that level on build decisions and attitudes!
It can be like trying to move heaven and earth. These are big companies they move like elephants in most matters of this type.

In short sometimes it pays NOT to rock the boat!
Believe me I have been there & in short I was often told "repeat the policy"! You will treat it like a serviceable item that is the edict from on high. Yessire!
I have even been in a meeting where commercial attaches from different embassys have complained about engineering policy. It can get that elevated.
Dennis