Thread: Making wiring harness?

Tweet

I enjoy wiring and my local parts store can source good 'XL' shielded wire. I'm thinking of making my own wiring harness for my hotrod and sourcing an under hood fuse/relay block from a junker car and a marine 12 circuit fuse block from Iboats. Screw Terminal Blade Fuse Block ATO/ATC 12 Circuit - Blue Sea Systems 5029 - iboats

Will this work? Seems 12v from the ignition switch to a relay from the relay block, would turn that on and I could complete all my systems.. I could even buy a second 6 circuit block and then run that so that it functions when the key is turned to 'acc' for things like the radio, but have it turn on with the key in the 'run' position also, so that I had 18 circuits

Sounds like a good plan and that block looks like a good piece, even uses the "new" blade fuses.

Sounds like a good plan, other then all the different colors and sizes of wire that you need to buy, then all the ends, etc.....how much do you think you'll save????

Here's one from Speedway, used a few of them on projects. It has 20 circuits, includes a GM style headlight switch, dimmer switch, GM style directional light connector, all the terminal ends, splices, flashers, and all the other things you'll forget to buy and have to go get when you build your own harness.....

http://www.speedwaymotors.com/Street...turer=Speedway

I expect I might just break even of buying the cheapest wiring kit, But I like wiring... $159 for 20 circuits is something to think about tho

Originally Posted by Matt167

I expect I might just break even of buying the cheapest wiring kit, But I like wiring... $159 for 20 circuits is something to think about tho

You're going to use multi-colored wire to segregate circuits, buy all of the connectors plus the switches, flashers, fuses, etc and do it cheaper or as cheap as a pre-assembled kit? I don't see how that's gonna happen, but power to you! I think you'll end up investing 2x with the pieces parts method, and none of your circuits will be identified by conductor labels.

I haven't checked to see what the auto parts store can get as far as various lengths of wire without having to spend on 100' spools but I know he can get me the good wire. I know I need 1 color for each circuit + All connectors, relays and fuses.. I was planning on checking the prices before I purchased anything beyond the relay block which will only cost a few dollars from the junkyard.. I have a boat which will need rewiring also, but that entails 2 lights ( Navigation and Anchor ) and a horn if I go back to stock. and may add a VHF and some interior lighting but still, I can't justify having 50+ feet of 10 colors for 5 circuits.

Yeah, but - sometimes it ain't all about the price!

None of us built a car and based our decisions all about the pricing! I know some of my decisions were just purely because I wanted it! Don't need any other reason.

Yea, that's true.. I'm actually thinking of just doing it for the experience. I've made things like fog light harnesses and aux harnesses before but nothing big... I have yet to buy anything from a street rod vendor. Everything on my hotrod was either built by me or sourced from the junkyard. Only 2 catalog items to date were the Jegster ladder bars and some Ebay sourced coil overs because I'm not going to take chances with self designed suspension components.. Any extra supplies can get used on the boat as that wiring was never right from the factory. I pulled the top cap and found 2 conductor lamp cord running to the navigation light in the bow, and I'm pretty sure it's factory. Boat was built in 1961 by a failing company ( Custom Craft ) so quality was a bit shady.

The hotrod will also tow the boat ( 1,090 lbs dry on trailer ), so I need to intergrate a HD flasher and trailer wiring connector into the harness anyway.

I know for me there are times that I just want to do it for the same reason(s), the experience. I just want to say I did it.

Matt, I agree 100% with Mike. There's nothing wrong with doing things for the experience, and to make them "yours" as opposed to buying a package. I got off base by Dave's comment, asking how much you thought you'd save, and cost was not a consideration in your original post. I like that compact fuse block with the "weather cover" a lot more than the one in my "kit", and with an understanding of basic circuits, relays and conductor sizes there's no reason that your plan won't work. I'd say go for it, and any wire left over will be a starting place for the next project!

Matt, I’ve been building my own harnesses for many years. I personally find it enjoyable and relaxing. When I have a project under construction, I usually start looking at the part store wiring section for the different color and gauge wiring and pick things up a few items at a time to spread the cost out and try and make sure I have I need when I get to that part of the project.

I few things I learned along the way that might be helpful:

List out your circuits/accessories.

When you start building the harness, draw your wiring diagram as you go, making sure you include wire color and gauge. I usually draw each circuit in as I complete each one.

On complicated circuits (stereo, ignition, cruise control), make a separate wiring diagram which will be easier to read if necessary.

Add a couple of extra un-terminated circuits to the rear of the car and engine compartment in case you want to add something later on.

Protect with headlight circuit with a circuit breaker rather than a fuse.

I usually run a Ford Solenoid (even with GM and Chrysler starters) in a convenient location …….it makes it a lot easier to hook a remote starter switch and if you ever have to remove the starter you only have the main cable to remove from the starter.

It’s a lot cheaper to buy the terminals and connectors in bulk than the small packages and if you do your own wiring they do eventually all get used up.

Thanks for the tips. I planned on using factory relays in a relay block for the headlights and other high current circuits, but I know there are circuit breakers that replace ATC fuses and they are not that expensive.

This truck won't have much except it will have a heater, possibly even A/C.. Beyond that I plan on a stereo and an interior dome light that will operate with a switch on the dash. Other than that, just basics, turn's, brake's, headlights with high and low, and dash ilumination... Oh and a set of those electric safety locks for the doors as I'm using the Speedway 'T' type door latches.

I was at the junkyard today getting a new air conditioning compressor to replace the seized compressor in my Subaru and also a new trim strip to replace the missing strip. I got an under hood fuse/ Relay block from a 1998 Subaru Legacy 2.5GT and another from a '94 Ford Escort. With one or both and the marine fuse block I should be set for a start. I have factory manuals for the Subaru and I have a Chiltons that covers the '94 Escort so I can figure out what is what in them.. The checkout person waived the cost of the trim strip for me which is usually $10/foot ( 2' piece ), so I came out a bit cheaper than I should have.

Hey Matt,
I doubt you will beat the price of a kit by building and buying all of the components to wire your car yourself but, if you decide to forge ahead. Look to this guy for your wire.
This is an excerpt out of my Astro build...

As I have been pulling together the wiring I have found some excellant suppliers with high quality products. The wiring books were a couple and here is another.
If anyone is in need of automotive wire give Nate Garland at Welcome to Wire Barn - Your Trusted Wire and Supply Source a look. He sells a number of different types with GXL cross-linked polyethelene being one of them. This stuff is a far cry from your basic PVC covered junk.
He sells it in 25' lengths in multi-packs of six or eight colors. This is perfect for a home builder like myself as I don't need 100' spools of wire laying around. It's also a helluva lot cheaper... I just bought 1 ea. of the 18ga, 16ga and 14ga 8 color packs from him and paid about what I would have for four 100' spools of 16ga. This is more then enough wire to finish up the van and probably a couple more projects down the road. With 8 colors and three ga sizes I am pretty well set for wire for a while. He also has 12 ga and I'll be picking up a selction of that this week.
Here are some pics of the wire he sent me. It is very nice stuff. And it is made in the USA!!!

Got that place bookmarked. what he charges is basically what the parts store gets for PVC coated wire..

Originally Posted by rspears

Matt, I agree 100% with Mike. There's nothing wrong with doing things for the experience, and to make them "yours" as opposed to buying a package. I got off base by Dave's comment, asking how much you thought you'd save, and cost was not a consideration in your original post. I like that compact fuse block with the "weather cover" a lot more than the one in my "kit", and with an understanding of basic circuits, relays and conductor sizes there's no reason that your plan won't work. I'd say go for it, and any wire left over will be a starting place for the next project!

Yep, it is nice to be able to say I built it. It's not perfect, plenty of non traditional components were/ are being used on it, but everything was fairly inexpensive and it will be a safe ride.
Next project is arleady thought of. Tho it will probably have to wait a couple years or better, I may build the body for it out of fiberglass with leftover supplies from redoing the boat's decking and transom. Have no clue where I'll store it tho. Probably easier to store 5-10 gallons of resin than it is to store a car body