I heard a few individuals pop the 350amo fuse in the trunk near the battery, but I do t see anyone talk about how????


Driving the car down the interstate and it popped the fuse and killed the car... Coasted off the road and nothing would power on....

Plan to hopefully figure it out this soon.... Car is sitting in my shop at the moment... Since I'm pretty heavy modded I did t take it to the dealer

Any suggestions???
I'm stumped on electronics

 

Anyone have any info?

 

A service manual is very helpful with electrical issues but in this case you most likely have (or at least had) a major short to ground with the high current feed running to the front of the car. I recall one person had the fuse open because of the engine being locked up (excessively long bolt included with a modification kit but this would happen at initial start and not just when running down the highway) and unable to turn so the starter motor (which draws extremely high current if the engine cannot rotate) must also be fed via this fuse. The starter doesn't draw current unless the starter was engaged so that isn't the issue in your case.

A 350 amp fuse that has gone open generally creates obvious signs at the point of the fault (spattered metal, burned insulation) because you would have had in the neighborhood of 4 kilowatts of power being dissipated at the fault point and this can help identify the location.

While working around a battery remove rings, watches, etc. I remember in high school a classmate nearly cauterized off a finger when a ring got between the positive battery terminal and ground; the battery can source several hundred amps easily. If you have a DMM or VOM I would start by disconnecting first the negative battery cable (for safety this is always the first cable to remove so you don't accidentally create a short between the positive terminal and ground with a wrench) then remove the positive cable and measure resistance to ground to see if the short still exists. If the short still exists be careful moving cables around without closing examining each one because you don't want to clear an intermittent short without first clearly identifying where the fault lies.

Look closely around the starter to see if the heavy positive lead to it has contacted a hot engine part and burned through the insulation, also examine closely where the cable goes to the fuse block in the engine compartment. Odds are this is related to the modification work where either the current carrying cable wasn't secured OR an installed part is too close to the cable and the heat damaged the insulation. Another possibility is the cable was either pinched or is rubbing along a metal piece and the insulation was damaged. With this sort of current discharge the damaged area should be easy to see.

Good luck!

 

Great reply.... Car is sitting in my shop and I'm away for work, but Friday I plan to check it out with one of my good friends who's a GM mechanic,...

He mentioned when I pulled the starter, when I installed it, it may have been too close to the exhaust???
Drive the car for 3 days and then this happens... For it to blow THAT fuse... Something happen!!!

 

Hey I just had the same thing happen with my 350 amp fuse would you mind sharing what it was please? Tearing it down now must have a short somewhere???

 

It would have to be a short on the main positive battery cable to blow that. Just follow it.

 

I was able to jump it temporarily with some TIG wire and start the car, but it would the melt the TIG wire and shut off. I first checked continuity on that wire to ground and got nothing, hence no short. If it was shorting I should get some continuity back I would think. Regardless ordering a couple new fuses and will check the wire all the way up to the fuse box under the hood. Thanks.

 

Mine blew the day I drove it off the dealer lot. None of the systems powered by the under hood fuse box worked. Systems powered from the rear fuse box did work. Car would not start, nothing on dash, and had to use the emergency door openers to get out of the vehicle. We do not know what caused it. Dealer couldn't find any sign of a short anywhere, and you would think blowing a 350 amp fuse would leave a few telltale signs. Dealer replaced the 350 amp fuse block with one from another car on their lot and it has been fine for 3 months and 1300 miles since then. 2019 Z06. Fingers crossed that it does not happen again. Fuse block is about an $80 part. GM Part 84314829

Here is a picture of the part.
https://www.tascaparts.com/oem-parts...e-box-84314829

I ran across a blog where this part was completely corroded on someone's C7, so it's worth looking under the battery cover once in a while.

 

I had the same thing happen two weekends ago. Waiting on the new fuse panel to show up. A buddy of mine that works for Lingenfelter says this is the third one he has heard of doing this. The other two being at his work. GM definitely has a defective issue going on.

 

Wow this is incredible. I thought for sure a short would be the ONLY way to blow that monster fuse. I ordered 4 they will be here today (overnight) going to see what happens. I also ordered a new under hood entire fuse block (long story but that one got wet and corroded a bit) just to be certain no short was in there. It was $180 shipped. I checked for a drain by putting a test light and meter on the negative battery cable and pole and got nothing. I am going to check the main battery cable also just to be sure no insulation rubbed off near my headers or under the fuse block. I have a CRFueler Holley port injection system so I have tons of wires and mods right where that cable is possible it rubbed on some metal. But it's not shorting now but I will ensure it's not going to be some future problem.

Thanks for the info guys very helpful! I really thought my motor was toast at first. Scary but at the same time I will just pull it and rebuild, not the end of the world. Either way I will take a $20 fuse over a motor all day long. Wish me luck!

 

The shitty part is what is the fix? I tried to buy an individual fuse and couldn’t get it to work. So I ordered the entire OEM fuse panel. My brother was logging my car after making some adjustments with the new fuel system upgrades and the car shut off and left him stranded in a shitty part of town. Was a total PITA

 

I couldn't find a part number for that fuse individually. Curious what you came up with as an individual fuse replacement. The ones I saw on fleabay and amazon don't look like they mount onto the block. Good luck with your fix.

 

Here is what I ordered. Tap the link

Fuse Box

 

I installed a new fuse and it popped right away as the car went to start. Must have a direct short related to the starter. Weird part is the car randomly shut off driving down the road. Maybe the wire got close to the exhaust and shorted out and shut the car off originally. Will find out soon enough.

 

Good luck with the fix and let us know what the problem is. Might have fried the starter or solenoid. 350 amps should leave a few telltale signs.

 

You can order individual fuses and take the old 350 amp fuse and bend it back and forth to snap it near the base. Then you can simply use single fuses from now on over the ridiculous engineering design of one fus blowing forcing you to replace an entire fuse set of 6 at once. I will get some pics.

My problem ended up being a bearing failure. So my engine is essentially done for. I have big HP so wasn’t too surprising. Going to order a new LME short block with forged internals to handle 1400 wheel HP and swap my upgraded heads and parts over to it. The motor cranks over with coils unplugged but if it runs it seizes up pretty fast it’s for sure a bearing failure. I will have it pulled apart soon.

 

Wow. 350 Amps!

Sub'd

 

Well I found the culprit...my blower locked up. Put the transmission in 4th gear 1:1, rolled it back and forth after marking the belt and the engine turned over but the blower pulley didn’t budge. Pulled the belt off and the pulley wouldn’t spin. Pulled the blower lid off and the back of the rotors are hung up on the inside of the case.

 

Ouch, that really sucks!

 

That sux. Hope you get it resolved. Would also like to see a pic of what C5-VERT is doing so that you don't have to buy the whole fuse block when the 350 blows.