Some part of my battery cables is causing the truck not to start. It won't turn over, so I wiggle and reposition the negative cable close to the terminal and the lights and stuff go on, as I temporarily get my voltage back. And if I position the cable just right, the truck starts.

My battery is less than 2 yrs old. No corrosion on the terminals. My negative cable has a spot where I accidentally grinded through the insulation down to the bare wire. I wrapped that spot with electrical tape. I don't know if this would cause the issue.

It looks like replacing just the negative cable is a daunting task. There's an entire harness with multiple cable shrouds that goes along with it.. What should I do?

 

If the wear spot happened a while ago, check it to make sure the copper didn't corrode. After that double check that all connections are clean and tight. You could also bend the cable all along it's length and listen for crackling from broken copper for jab it with a multimeter lead, clamp the other lead to the neg. terminal, switch it to beep with continuity, and bend the cable around. The problem with using the meter is that you'll end up with holes in the insulation that water can get in through..

or heck.. just run enough juice through the cable and wait for a spot to get really hot! (kidding)

 

I checked that spot i grinded through and its fine. Its just a tiny spot anyway so i guess that's not the culprit.

I think it was just some light corrosion on the leads that i didn't know was there. It didnt look like any was present, but i scrubbed it anyway, and sure enough, I could see it going airborne. The truck starts fine now even with the negative cable back in its original spot.
The last time I got new battery terminals (in March) i put a bunch of dielectric grease all over them to prevent corrosion, and they still look good today, but I still got alittle buildup on the leads inside the clamp. Corrosion is some sneaky sh*t

 

IMHO… Sounds like you have connection problems, maybe corrosion but it doesn’t matter because you are moving the battery cables terminals around to get connection then you either don’t have much left of Terminals or they are just plain dirty connection.

Start by just cleaning the battery terminals, adding some terminal paste, making sure the Cable Connections clamp as well as they are able to; not loose at all. If you can turn the terminal be hand after tightening then it is time to replace them.
Do not use the Quick Fix Replacement Ends, yes they work for a while and that might get you through but they will act up again down the road when you need the ride and it won’t start.

Replacing both cables and get it over with; if the truck will remain stock then replace with std gauge cables but if you intend some sort of upgrade, i.e. stereo amp, lights etc then buy one or two sizes up in wire gauge size, if 4-ga then go to 2-ga or “0”-ga cables. They cost a little more but will help out in the long run.
Make sure to run a Post Cleaner on the battery posts and on the inside of the Cable Terminals and then use a good Battery Terminal Paste to help reduce corrosion in the future and make these cables last the remaining life of the truck.

Also, make sure you get a good connection on the ends opposite the battery on both cables.
Clean them well, add external tooth lock washers, HD versions, add anti corrosive paste and tighten BUT not too tight. The ends can dimple and cause the end of the cable to split so use a good quality tooth type lock washer and “not too tight but tight enough”.

Luck,

p.s. After the battery cables are replaced, look at other cable from the battery area to the engine or frame, if they are corroded/rusted then replace them too.
A trick that I use for a good starter response is to either run a engine ground cable from the battery/frame to one of the starter bolts or maybe an extra cable to the starter bolt directly from the battery.
That way the starter get all of the current flow that it needs to spin over.

 

maybe I'm wrong cause I've never done it before, but it looks like replacing the battery cables is a major PITA, and it looks like I may as well just go to the stealership and get an entirely new battery harness with all those other cables that run to the PDB and all the other stuff, and just replace the whole thing. I don't even know how I'd go about replacing just the + and - battery cables. There's alot of wire shroud that would have to be cut, alot of it deep in the engine bay and that shroud is also holding other cables. It seems like I'd have to pull the engine just to do this.

 

What was your solution?

I'm in the same boat and noticed just what you said above... doesn't appear to just replace the negative cable, the whole LOOM of wires need replaced?

-Nigel