View Full Version : Wiring harness choices.
rickyracer
08-11-2025, 11:41 PM
I am rebuilding an MK1 and am in need of a new complete wiring harness. I have narrowed it down to a Ron Francis or a Painless system. Just wondering what you are using and why. Electrical is not my strong point so I want simplicity as much as possible. I will be running just basics electrically.
Thank you.
edwardb
08-12-2025, 05:25 AM
You'll get different opinions on this. But if you're not real strong with electrical, the Ron Francis harness may be your best choice. It's purpose made for Factory Five and the wiring manual provides a suggested layout and everything is marked according to purpose. Hasn't happened to me, but several on here have reported mis-wired connectors. I wouldn't use that as a decision factor. A universal harness like from Painless, American Autowire, etc. may appeal to some because of the perception of higher quality or more flexibility for making changes. But the RF might be your best choice IMO.
Bob 5.0
08-12-2025, 06:48 AM
I have a mark 1 and I used a Kwik wire harness! Was super easy, and they can tailor it to your needs. Came with a hole book with step by step directions, and pictures. You can also call them with questions and they will actually answer the phone and help you out with any problems ! Wisconsin based company
Good luck
rickyracer
08-12-2025, 03:21 PM
Thanks guys for the great info. Much appreciated.
Mike.Bray
08-12-2025, 03:29 PM
From experience Painless is painful. American Autowire is very good and the RF harness is made for the Factory Five cars.
Nigel Allen
08-13-2025, 02:04 AM
An advantage of buying a Ron Francis wiring kit is not only will it be suitable for the cobra, but it is much more likely that you can get some tech support from guys on the Forum if you get stuck. There are many that are quite familiar with this wiring loom. Yes it does have some issues with quality control but overall is probably the best way to go. There are a few people in the Forum that haven't used theirs, so you might be able to buy it from someone here.
weendoggy
08-13-2025, 07:55 AM
I've used Painless in builds for over 25yrs without any issues. It all depends on a lot of things, but in my case, I like to put connections where I want them, not where they want them. To each their own.
I didn't use the RF harness, only because I wanted to place my fuse box in the trunk. I chose to use a harness from Rebel Wire (http://rebelwire.com/) that's designed for this type of setup. I can't compare it to RF, Painless, or Autowire, but I was very happy with the quality. They're a small shop with great support.
I rewired a MK 1 a couple of years ago with a Painless universal harness. Everything was well labeled and straight forward. I've also done a couple with the RF harness. Given a choice I'd go with the Painless. Much cheaper and no more difficult than the RF. I seem to always end up cutting a lot of unused stuff out of the RF harness.
Bob