Cleaning up the wiring harness

[MB750]

Just asking the Forum to see if I shot myself in the foot on this one. I've got some electrical blood running through my veins so when I see messy wiring it goes right up my spine.

Now that I'm working my way through the wiring I'm staring at the rats nest behind the dash and my spine is itching me to do some house-keeping. First off, why is there wiring in this harness that's not even for this car? (I know the answer, I'm just annoyed...) For instance, that column connector that's about 3" wide. "Just shove it somewhere..." Yea, sure... *snip! (Don't worry, I pulled the wires back to the source and cleaned up the terminations)

And, since I'm using the GPS gauges why is there some wiring for oil pressure, oil temp, and water pressure still in the harness that I'm not using? (again, I know the answer, for use over multiple vehicles)

So yea, I removed a bunch of wire from behind the dash. Mostly from the Dash Harness, but also some going under the hood, and that column connector that's not even used on my car.

One of the last Harley's I built had absolutely no unnecessary wiring. It was also very minimal. Turn signals was the extent of the accessory wiring. I loved how clean it all looked and that's what I'm going for here. I could also pull the 12 VDC accessories (radio, heater, etc...) but I may use radio for a future 12 VDC accessory so that'll stay behind the dash.

[edwardb]

You answered your own question. The harness is used in multiple models and is made to accommodate them all. That 3" wide connector is used by the ididit steering column on the hot rod and truck. (Works great BTW) Doesn't hurt anything if not used but you're not alone to remove it for other builds. Oil pressure, oil temp, and water temp wires in the instrument panel harness can be used with any gauges including the Speedhut GPS gauges. I used them on my builds because I prefer to have all the instrument panel wires go through those two large connectors vs. directly wiring the gauges with the Speedhut supplied wires. Makes it easier to remove the dash if necessary. Which I've had to do on my Coupe a couple times. Bottom line, lots of flexibility for different models, build decisions, and layouts. Works fine as is. I agree though. Hard to make pretty without some surgery.

[MB750]

Thanks for replying. I just looked at that elephant trunk FFR calls a Dash Harness and thought there's gotta be a cleaner way.

I'm probably in the minority, but I would have preferred to get the harness as a bunch of connectors and rolls of wire. I guess now I'm meeting that in the middle. The rest of the harness is clean, except for where it's in close quarters behind the dash.

[Ted G]

In hindsight, I wish I would have done a major wiring harness diet. After a year or so of driving, if I need to get into that rats nest, I'll probably be lost.

[JohnK]

The harness works fine the way it is, but I agree that there's stuff in there that's not needed on every build. Depending on where you locate things on and behind your dash, the way the harness is routed and wrapped may or may not work for you. I was pretty tight on space so I ended up stripping 90% of the Ron Francis harness and the entire behind-the-dash portion of the coyote harness. I did some dieting but mostly this allowed me to relocate wires to where I needed them and adjust lengths accordingly. It was a bit of a PITA to strip and rewrap the harnesses but in the end I got a much better feel for the overall layout and function of the harness, and ended up with a result that I'm happy with.

[Tooth]

My plan was to keep it somewhat organized, and then clean it up when everything was working. But, I'm just winding up with a huge rats nest so far. :eek:

[BrewCityCobra]

My plan was to keep it somewhat organized, and then clean it up when everything was working. But, I'm just winding up with a huge rats nest so far. :eek:

I had to laugh reading this - I'm in the same boat right now. I did what I needed to to get my harness completed and in place with the expectation of going back and cleaning things up.

Time will tell.

[scrubs]

Will do a harness diet on the next build...ain't going back into that thing unless I have to on this one.

[MB750]

It's good to see I'm not the only one who thinks the harness needs to go on a diet.

[egchewy79]

electric work was my weak spot during the build. once i was happy things were hooked up correctly, everything else got stuffed behind the dash. I've seen some real works of art out there. I think 520speedworks offers this exact service, cleaning up behind dash wiring.

[OB6]

I've read of some people using a Painless harness (or equivalent) for the reasons stated in this thread, but there are trade-offs with that approach too.

[Sarcasticshrub]

I'm not in any hurry and really enjoy the r&d process. Or equivalent is where I'm headed. Not sure if I'll be using a complete harness from one of the big harness vendors or a DYI setup.

[CraigS]

I know it may not come up for everyone but I always recommend going w/ the FFR harness. My reasoning is when a question comes up about the blue wire in connector #X, at least most everyone here can have an idea of what is going on. I have seen Qs about there are a couple of wires to choose from regarding radiator fan operation and the temp sensor. I believe there are more than one way to wire turn signals in the harness. So which is best for a roadster vs a 33? But yeah, I agree the harness can be lightened a lot if you want to take the time to do it.

[CDXXVII]

I also got a little carried away cleaning up the Ron Francis wiring harness. Here are some pictures of the dash section. I also went through the rest of the harness and cleaned it up for my needs. I am an electrician by trade so I have a set standard as to what I like. The most current Ron Francis harness is a bit better but it is still designed to meet a few different setups.

I was not happy with the Speedhut daisy chain setup so I replaced it with a cleaner custom harness. Not a big deal but if I have to change out a gauge in the future I will need to make up a new connector.

If you make changes try and update the Ron Francis book so that you can trouble shoot if needed at a later time.

https://thefactoryfiveforum.com/attachment.php?attachmentid=124834&d=1585198683

https://thefactoryfiveforum.com/attachment.php?attachmentid=124835&d=1585198767

[Alan_C]

I did a donor built long ago. I had Art at Wire Diet thin the OEM harness as part of his dieting process. When he was done, the harness was part OEM and part EZ wiring harness. I think Art used something like the EZ harness below. Going this route there was not a lot of unused wires, but still plenty to work with. What I remember was the need to tailor the length of the harness where it ran across the front of the car and in the trunk area. I believe I shortened the harness on the order of 10 to 12 inches in both spots. Like you are suggesting, seeing a harness looped to take up excess length was a no go for me. If the unsued wires cannot be tolerated, get the car running and remove the harness wrap. You can then do your own diet after you are sure which wires can be eliminated. While you are in there, do a wire diagram for each leg of the harness. You and a possible future buyer will benefit from any documentation you do.

https://www.ezwiring.com/product-page/ez-wiring-21-standard-wiring-harness