The Stovebolt Site Forums The Shop Area Engine Shop Installing a new wiring harness

How difficult is it to install a new wiring harness? I purchased one from classic chevy parts and it should arrive next week. I'd be lying I said i wasn't a little intimidated by this project. Is it worth me trying it on my own (saying i am a novice at wrench work is an understatement), or have a pro do it? Any advice on starting up, time it takes, etc.?

Thanks,

Carlos

I wired my 1954 Chevy Belair bumper to bumper using a new Painless wire harness. Also converted it to 12 volts. Never wired a complete car before. Had numerous questions and the techs at Painless were a great help. Would I do it again, it would be easier the second time around. Considering a rewire on my 1955 truck. It takes alot of time and patience. Good luck.

its not hard just need patience and it will all come together in the end. find a wiring print for your truck and make three copies. use one copy when you remove wire from the truck and take a yellow highlighter and mark what you remove. when its all yellow all wire shoud be removed. prior to removing anything take another print and a multimeter, when you get the harness take that seven pounds of spagetti out of the box and find the front of the harness and lay it out in the box of the truck the same way its laid out in the truck. put any loose wires back in box for future reference. trace out the harness one circuit at a time. mark each end what it is for with tape. this will get you familiar with the electrical system before you actually do anything to it. when the page is all yellow all the wire ends should be marked and checked with the meter to ensure there no bugs with the new wiring. now you can start removing old wire as you do the two prints should start jiving with one another.

grab the new harness and find the wye in the harness for the headlights and voltage regulator and fish all the loose ended terminals through the hole in the fire wall without losing any of your marked ends. then orientate the rest of the harness. now take the third print and as you hook up terminals one circuit at a time take the highlighter and mark that off on the print. when the print is all yellow your not supposed to have any loose wires left. if you need to walk away from it, the print shows you where you left off. when your done check each circuit for proper operation. just remember before starting the truck when your done to polarize the generator.

make sure all your ground points are clean and rust/paint free. if a ciruit doesnt work then its a ground issue because you already checked the circuit while you were labeling the ends previously.

the first time i did mine it took two days. the second one i did one took one day. pre identifying all the terminals is time consuming but you make that back up when your actually attaching them because you already know where they are going.

I also bought a harness from Classic, I'm 99% complete and it was a breeze. All the wires were labeled and they had a direction sheet. It laid out perfectly. I don't know which harness you got, mine was $ 149.00. I had removed the harness prior to installing. Any questions you can pm me,I'm local..Santa Cruz Mtns.
Thanks

I used a Painless kit on my truck....same as you, I had never done any serious wiring work. I procrastinated as long as I could then took the plunge...actually not too difficult. Just take your time and make sure your connections are good. Some of mine I soldered as well as crimping just because I am paranoid.
Make sure grounding is good as well, and add ground straps between motor / frame, body / frame to ensure good connections. I got stuck a couple of times ( rear turn signals & brake lights ), but Painless techs. were good.

Thanks for all the advice and tips. I should be getting it in the mail this week and I am looking forward to giving it a try. I'll let you know how it goes. I particularly enjoyed 51 Ashton's approach of using 3 different copies and testing the wires beforehand. I encountered a few setbacks putting my fly wheel and clutch plate together, only to have to pull it all apart and do it again because I did not "measure twice".

Thanks again!

Carlos

I also bought the classic set (2nd full rewire job) and it was very easy to follow. I converted to 12-volts and they have multiple options for the different conversions in their directions. Make sure to save your schematics/drawings that come with it and scan a set to save on your computer. A few years from now wire #35 may be a mystery if you don't have the originals.

It is easy and you will not have any problems. I used one in a 55 2nd and plan to get one from Classic for my 48.

I'm not sure if I should convert to 12 volt or leave it 6 volt.

Howdy, I am about finished rewiring my '71 C-10. Over all, there is VERY little difference in mid '50s 3100 wiring and my truck. I made up some of the harnesses myself and used a really sweet used OEM harness under the dash. Now, every PO of my truck must have owned a big roll of black wire, a big roll of yellow wire and stock in Scotch Locks! There was evidence of at least two separate electrical fires. On top of all that, I decided that I wanted to be able to use high draw headlights and a couple of Hella 500s. Given the above, I built three harnesses for under the hood and one for the rear. The rear also got a built in trailer plug. The engine harness is all different since it now includes HEI and an electric choke carb. Then I built a MASTER power harness for power distribution and a to include a change to a 12si alternator. Then the lighting harness for the heavy lights with all it's Bosch relays. I could have done this faster and cheaper for basic wiring with one of several different kits.
I can build what I wanted so I did. This took about two weeks of spare time.

Everyone who gets into an older vehicle project, sooner or later gets to the wiring. It is a must do for your pride & joy to be what you want. SO, buy two 3/4" rolls of blue painters tape and a pack of those permanent felt tipped pens and a yellow note pad. Label Everything as you remove it! To much information isn't a problem. Make little flags out of the blue tape for each wire. Draw out a detailed picture of where the harnesses run and the plugs on all the switches. Take notes. Write down anything, such as, "about 6" from the cigar lighter I found a wire with a light bulb socket that doesn't go anywhere," so you can figure it out later.

Brad Alan's and 51ashton's comments above are on point about the extra copies of the diagram! There is never to much information about YOUR truck!

Take a deep breath and dive in! It'll be so simple it will amaze you, and it'll be one more thing you can say 'I did this myself!"

Now, I need someone to encourage ME on bodywork!

very best wishes,

Les

Brad, I'm trying to get a fuse box cover for a 1949 3600, do you have one?

Mike

I haven't done a rewire yet. I plan to on my 58 Burb when I get back to the states. One other comment I'll add is to make sure you have the factory assembly manual on hand. The wiring diagram is a great reference but it doesn't show the physical routing of the wires. When you go to put the new harness in you may not remember exactly where the right break light wires were routed/attached. The assembly manual will show you the way.

Good luck!!