Wiring harness swap....

[Bfitz]

I have an '85 k5 and the wiring is such a mess that i have decided to start from scratch. I bought a universal 18 circuit harness with a dash mount ignition from summit, and im ready to start install. My question is, what are the major do's and dont's when making the swap? I have been told it is a bad idea to rip it all out and start from ground up, so do you just gradually replace one wire at a time? All recommendations are welcome.

 

[toomany]

I've done it a few ways on my projects. If you a good with wiring, and know what you want. Then it's easier to start from the ground up. If you feel like you might get overwhelmed than I would do one wire/circut at a time. I prefer to rip it all out and build my own harness. These trucks are real basic when it comes to wiring.

 

[DizturbedOne]

REAL basic. You won't run much of anything to the rear, it's pretty much all under the dash. I was just under mine today, I need to do the same thing but money is tight right now and I have a bunch of other stuff to do first. Looks easy enough though. I'd upgrade your positive and negative battery cable along with your chassis to motor ground cable to 0 gauge while you're at it. It's big with stereo guys and is very cheap to add. It helps alot with current draw, especially if you add any electrical accessories (stereo, lights, winch) later.

 

[Brady]

I have been putting the same kit in my CJ/buggy.I bought the one that wires up to a GM column.I have never wired anything from the ground up and it has been relatively easy.Follow the intructions and study them.Keep good notes of what goes where.I layed the harness out and started on the rear first.Since this has the least amount of wired.Then went the front.Then started on the column section.Finishing with the dash section.Still not done totally.Mine is a TBI set-up so I have the added fun of that.But it did start the first time!
Be sure to run all wires in a loom and keep away from exhaust and moving parts.Use a grommet when passing through sheetmetal.I used wire crimps and a self sealing shrink tube.Got this from NAPA.I found myself lengthening some of the wires and dead ending some.I didn't remove any extra wires.I just put a piece of shrink tube on them with about 1/2" passed the end of the wire then pich the end shut when hot to seal it.Figured why remove them?Never know if you may need them.Ie,it is a buggy so I am not worried about back up lights.But am going to use the wire for a set of rocklights in the rear.No need for a radio so the radio constant will be for a CB.And so on.I know I am not covering everything,but hope it helps some.

 

[Bfitz]

Thanks for the feedback. Im about halfway done pulling the old out. It is not looking to complicated anymore.

 

[BoondocK5]

If you have any kind of memory at all, the thing shouldn't be too bad. That being said, I've never used an aftermarket harness. I always pull them myself from pick-n-pull and install them myself, chop out what I don't want, add stuff I do want.
Kind of time consuming, but it works.
The wiring harness in my Blazer has parts of 4 different trucks in it. You would never know it, because I spent the time to make everything right.