ZR2 Battery Distribution Block Gremlins

[boilerup]

I bought a '24MY ZR2 in November and have since been loving the truck. I've already put 7000 miles on it but for the first time a few weeks ago it finally let me down. I did a hard acceleration to pass traffic and as I was coming down from the pull (coasting), the trans went into neutral and the engine shut off.

I managed to get it pulled into an empty parking lot and attempted to restart the truck, which resulted in a no crank. Truck threw zero codes and upon further roadside inspection using a multimeter, I found that the 400A fuse ontop of the battery had blown, causing the starter to not engage. Managed to jump the fuse and get the truck to the dealer where they could not find the cause of the issue and simply replaced the fuse under warranty. So this poses a few questions.

What equipment runs off the 400A fuse? What would cause the engine to shut off and blow that fuse? My first thought is alternator but surely an alternator failure would throw a code, and also not affect the engine.

Anyone have ideas?

 

[ZR2BIZON]

Welcome, sorry about that fuse making you join the forum.

I'm not a scientist but, it could be the hard acceleration caused a surge from the alt. to blow the fuse which should have never happened but we have been experiencing electrical ghosts here off and on. Again I'm not a scientist.

 

[boilerup]

I've been lurking on here since before I even got the truck so I figured now was as good a time as ever to do it.

Could be a surge from the alt but my question is does it reside on the same circuit as the starter? (400A). If so, that makes it more plausible but if not, I need to keep chasing down other possibilities

 

[ZeroRest2]

According to the wiring diagram it looks like that fuse is for the starter only. Alternator is 250amp.

 

[DNZR2]

Unfortunately fuses don’t just blow for no reason. Something had to have shorted even if was only momentarily which will make it hard to find.

 

[boilerup]

That's what is irking me so hard. Sudden engine shutoff, blown starter fuse in conditions where the starter circuit shouldn't be activated. Ground strap looks good and I can't find anything that would suggest physical short. On top of that zero codes

 

[22-ZR2]

Maybe carry a spare fuse until they get it figured out if it even ever happens again. Sounds like the Dealer has no clue on the cause.

 

[HighTechPauper]

It is rare, but not unheard of, for a fuse to be weak at manufacture and blow at well below its rated amperage. Maybe just keep an eye on it, it is possible it was nothing more than a weak fuse, and if it wasn’t that, it should blow again sometime soon, and I would try to find a location I could safely do a few hard pulls to try and reproduce. IMHO/YMMV

 

[ZeroRest2]

Did you try pressing down your fuses. Many of us had loose fuses from the factory.

 

[scubatech]

That's what is irking me so hard. Sudden engine shutoff, blown starter fuse in conditions where the starter circuit shouldn't be activated. Ground strap looks good and I can't find anything that would suggest physical short. On top of that zero codes

400 Amps could power the whole truck! I'm guessing it was a weak fuse, like High Tech Pauper stated. Good job finding it!!

 

[AXE]

400 AMPS = electrician and shielding gloves and FR gear.

#sparky

 

[Floriduramax1]

I’m in the cheaply made faulty fuse camp. I buy lots of fuses and low voltage breakers in my RV biz and I had to tell purchasing to stop buying the larger “buss type” fuses from Amazon due this same type of issue. Just think of how many years and how many vehicles were produced with the battery cable going straight to the starter with no fuse, only fuse-able links in the alternator circuit!

 

[boilerup]

Quick update to this, pulled the filter. There was metal but I chalked it up to debris from the casting. Initially I was hearing a ticking, chalked it up to maybe loud injector lifter, whatever. Fast forward 3 months and a few thousand miles later, truck does the same thing. However, upon startup after it randomly dying again. Knock knock it's your bearings. Very noticeable and there is no doubt in my mind anymore that the bearings had spun when the truck first died and the starter had just enough juice to break the crank free.

Moral of the story, if your truck dies and starter fuse blows - insist on getting the filter torn inspected and your bearings checked.