HMMWV Grounding Kit Install

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TROY, MO
I watched this video while in Tractor Supply gathering 10ga wire & connectors. I plan on installing right after I install my new fuel tank. Thanks for the info!!
 

LouWon

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Just did mine with the Kascar kit, quick and easy.
I also added an extra cable from the local shop between the heads, overkill...but it's done.
Next project
 

Jon0249

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I'm a DIY'er to a fault, so this was a rewarding project. Electrically speaking, the more wires in the cable, the better, which means it will feel heavy and very flexible, similar to a jumper cable. I picked up a length of 6-3 electrical cable 6' long, then stripped the shielding to yield all the wire I needed. The end product is a highly conductive system of 6 ga wire (approx .25" conductor dia), soldered all connections and fastened using star lock washers. Great preemptive fix. Thanks for the ideas and pics.
 
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papakb

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I did this modification years ago and have never seen a lot of the problems mentioned here. I used a very flexible 8 gauge wire to build the harness. I wouldn't use solid wire as vibration will break it in time. One of the weakest points in the HMMWV body grounding is the ground behind the heater controls where it comes through the body. My solution was to take a piece of 1/4" all thread brass rod and bolt it firmly to the body using star washers to guarantee good electrical bonding and then all of my wires attach with a separate nut and star washer so the mounting nuts never get disturbed. And as mentioned in other posts, anti-oxidant grease helps keep things corrosion free. It's cheap insurance.
 

NormB

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Did the grounding kit install from Kascar. It took me about 2 hrs. Personally spent too much time walking back and forth in the shop getting the right sockets, so here is my contribution to this thread;

View attachment 696337
It's those metric ones that really throw me. Any rhyme or reason to this? And thanks for that, could've used it about a year ago.


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juanprado

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It's those metric ones that really throw me. Any rhyme or reason to this? And thanks for that, could've used it about a year ago.


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Engines originally sourced from GM and they adapted to metric long ago. Military still prefers SAE for less tool and bolt proliferation.

Most OE vehicle manufacturers have switched to metric.
 

NormB

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I did this modification years ago and have never seen a lot of the problems mentioned here. I used a very flexible 8 gauge wire to build the harness. I wouldn't use solid wire as vibration will break it in time. One of the weakest points in the HMMWV body grounding is the ground behind the heater controls where it comes through the body. My solution was to take a piece of 1/4" all thread brass rod and bolt it firmly to the body using star washers to guarantee good electrical bonding and then all of my wires attach with a separate nut and star washer so the mounting nuts never get disturbed. And as mentioned in other posts, anti-oxidant grease helps keep things corrosion free. It's cheap insurance.
My local ACE hardware store has those trays full of nuts/bolts and doodads like you see at Tractor Supply and other, similar, stores.

Poking around one day I discovered they had ALUMINUM screws/nuts/bolts in a couple trays. I've since used some of them to make better grounds with the body, and, as there is no dissimilar galvanic corrosion possible (aluminum oxide is an INSULATOR, not a conductor of current, unlike copper salts which DO conduct), I slathered the connections with corrosion-inhibitor for aluminum-copper connections - forget the name but it's black, and messy - like you'd use in your home breaker panel in the days of aluminum wiring, and used heavy dielectric grease OUTSIDE the connections to limit oxidation.
 

NJPShorelife

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Asbury Park, NJ
I purchased the Grounding Kit from Kascar (PN 535-A1) and installed it over the weekend. I know it's cheap & easy to make one yourself, but I don't have much wiring experience and for $70 I figured I'd get it right the first time. It was a quick & easy install. Here's a write-up in case it helps anyone out!

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Great Pics.! I used / referenced this and posted a short video on my YOUTUBE channel.
https://www.youtube.com/watch?v=jge5opMXmjw
 

twisted60

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Jupiter, Florida
Just to jump in, I bought 4awg welding wire, looking to make up harness from this stuff with copper ring terminals. Could have bought the pre made unit but like so many others I like to get dirty, best way to learn about what you are working on. 4awg may be too thick, will have to wait and see, better to thick than too thin.

Thanks to all for posting the pics and videos,
 

Casasenita

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I bought and installed 2 Kascar grounding kits easily with the help of the above video. I ran into trouble with the 3rd install. The grounding bolt in the starter sheared off and then the bolt for the ESS is stubborn. I am attempting the aft bolt to connect to the ESS. Can I use the front bolt as an alternative? Since I am here, I will gladly take advice on removing the sheared starter bolt.


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papakb

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Casasenita, the purpose of the grounding kit is to make sure there are no potential (voltage) differences between any of the components in the electrical system and the body of the truck so any point you can pick up will generally work. You always want to use "star" washers because they will break through paint and guarantee good electrical connections between the various pieces in the system. This is not a current carrying loop so heavy wiring isn't necessary but you do want wire large enough to ensure low electrical resistance. That's why 8 gauge wire is used. Any one of the 4 bolts on the ESS/PCB will work as will any of the starter mounting bolts. You do want to be careful not to overtorque things and for stubborn hardware I've found that Kroil or AeroKroil is the best for loosening things up.
 

Casasenita

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Ohio
Casasenita, the purpose of the grounding kit is to make sure there are no potential (voltage) differences between any of the components in the electrical system and the body of the truck so any point you can pick up will generally work. You always want to use "star" washers because they will break through paint and guarantee good electrical connections between the various pieces in the system. This is not a current carrying loop so heavy wiring isn't necessary but you do want wire large enough to ensure low electrical resistance. That's why 8 gauge wire is used. Any one of the 4 bolts on the ESS/PCB will work as will any of the starter mounting bolts. You do want to be careful not to overtorque things and for stubborn hardware I've found that Kroil or AeroKroil is the best for loosening things up.
I appreciate the advice, Papakb. I removed all the connections and added star washers, connected to a front bolt of the ESS and will definitely try Kroil for future projects. As for the starter bolt, I was successful in using an extractor to get the remainder of the bolt out. The two hmmwv’s that had easily removed starter ground (negative terminal) bolts were coated in a protective rubber to prevent corrosion. The one I could not remove had no coating and considerable rust. I will be adding something to protect all 3 starters soon.


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StackJ

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I bought the kit from Kascar a couple of weeks ago and installed. Two things: My grounding was on the passenger side head. I went ahead and grounded to the drivers side head. Second thing: The gauge of the wires appeared to be "lighter" than what was shown. I don't think it makes a difference in the long run.
 

NormB

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I bought the kit from Kascar a couple of weeks ago and installed. Two things: My grounding was on the passenger side head. I went ahead and grounded to the drivers side head. Second thing: The gauge of the wires appeared to be "lighter" than what was shown. I don't think it makes a difference in the long run.
Ground wires generally don't need to be as heavy a gauge wire as the hot lead.

Current only needs to "sense" ground so it "knows" which direction to go, otherwise it sits in storage (battery, capacitor) waiting.

I found it very interesting that the 30 (THIRTY) amp-rated (might be higher, but that was the largest circuit breaker in in the kit) Power Distribution Unit (found on many later models in the battery tray/box under the commander seat) has only a 16 (maybe 14) gauge wire to go to ground.

Makes a lot of sense when you think it through. Current is the flow of electrons from high potential to lower potential (ground) intended to convey the stored energy to something which converts it to something else (light, heat) through resistance. If all that energy is flowing, lighting up the road, there's NOT a whole heck of a lot of energy returning to ground, or shouldn't be. If there's TOO much the fuse or CB breaks.

Ground wires? You're probably fine with 14g, even silicone spark plug wire (insulated for what, 30kV?) is probably overkill.

NB
 
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