Ron Francis Wiring Harness Dieting Questions

[Jim Doak]

I'm ready to begin wiring my car and I'm wondering if there's any information available about how to diet the Ron Francis harness.

I've searched the forum and have found threads where builders have mentioned dieting their harness, but I haven't seen any "how-to" descriptions.

For example, I don't need the "Hot Rod" section of the harness, so I want to get rid of the connector as well as the unnecessary wiring. So how do you guys do that? Is it as simple as unwrapping the harness and tracing the wires on the connector back to their source and then clipping or disconnecting them, or is it more involved than that?

On my first Roadster, I re-wired it using a Painless Micro Harness, which had around 12 circuits or so. This Ron Francis harness is much more extensive, and I'm sure it'll ultimately make wiring the car easier, but there's a lot of unnecessary wiring and circuits that I don't need or want.

[egchewy79]

You can just remove the sheath around the wires and strip out all the wires you're not using.
I just cut off the connectors that I wasn't using (i.e. hot rod section) and taped/heat shrink'd the ends and tucked them into the plastic casing.

[dbo_texas]

Yep you pretty much got it. There are different ways to do it --> you can unwrap any circuits not being used (like the Hot Rod leg) and trace them back to the source and disconnect. Or you can clip the wires and tape/heat shrink the ends so they don't short and then tuck them back into the loom. It's manual and tedious but helps clean up the wiring for sure. Just make sure you are positive you won't need the wire later - if you think you might, it's best to keep it and tape/shrink the end and just tuck it back into the loom. But for sure the hot rod leg can be removed completely for the roadster build.

[edwardb]

As others have said, if you're not building a hot rod or truck that use the hot rod connector (goes into an ididit steering column) you can safely remove it. Just to emphasize though, those are live wires. They are actually parallel connections off other circuits. However deep you go into the harness, once you clip the wires, my recommendations are to (1) clip at different lengths, (2) bend the end over 180 degrees, (3) install a piece of shrink sleeve. That way there's no chance for them to touch each other or something else that would cause a problem. Of course it's possible to take them all the way back to the source and remove there. But that means unwrapping a whole bunch of the harness which isn't really necessary for a Roadster.

You will see some builds (like a couple of mine...) that unwrap much of the harness and reconfigure. That's mainly because while it's a universal harness and sold with various kits, it fits the Roadster best. Also because some of us can't leave well enough alone and OCD takes over. But there's plenty of room in the Roadster to leave the harness as is. No overriding reason in general for dieting. Especially if you're not fluent in automotive electric concepts and methods. Fit it behind the dash and elsewhere as best you can and it will do the job.

[i.e.427]

I go way deeper into the weeds than most. Since we are always using a turn signal switch and not a dash mounted toggle, I always remove those wires from the dash harness other than the indicator light section. I also re-route the purple wires to the back of the car that don't get used any longer because of the rectangular tealights. One purple wires get used for a constant power for a trunk light we attached to a tilt switch so it turns on when the trunk is opened.

Now you can go the other way and use the Hot Rod harness end and take it to the turn signal instead. You still need to clean up some of the turn signal wires at the dash, but the harness is already there and all of the wires you need for the turn signal as well. One of my favorites is moving the hazard switch to the area next to the windshield post but behind the dash. I also put the headlight switch there. The other favorite is now moving the inertia switch over to the passenger side firewall extension piece. It gets the inertia switch out of all of the clutter that seems to accumulate right behind the steering wheel.

Frank

[Nickjj]

One other thing to take note that any unused wires in the RF harness can be repurposed for other uses making sure both ends are not connected to something else in the wiring harness. For example I am installing a Holley Sniper 2 PDM (power distribution module) which cleans up the wiring for the EFI system as well as provides a Fuel pump relay and fuse in the PDM itself, It also provides the radiator fan relay and control. Holley recommends a larger gauge wire to be run from the PDM directly to the in tank Holley fuel pump I am using. I ran the new larger gauge pair of wires down the rear RF harness and will repurpose the existing fuel pump pair of wires in the harness for a lower mounted reverse light, which is not part of the rear taillights that came with the kit. Also reusing the pair of wires in the RF harness for the transmission speed sensor which won't be used since I purchased the Gauge package with the GPS for the speedometer. The speed sensor wires will connect with a relay to the Tremec TKX transmission reverse switch terminals. Still a little wiring connections to route but spend the time now to think about the future and add or remove what is required.

Nick

[MB750]

My "diet" consisted of isolating all the end connectors that were useless, tracing their wires back to their origin, cutting each one at a slightly different length to prevent shorting, and using Scotch 33 to tape it back together.

[JMD]

I think you will be able to figure out which wires you need and which you don't as you go and terminate as needed. As a whole, the wiring was a bit intimidating but if you take it one step at a time it is fairly straightforward. Whatever questions you have as you go have probably already been answered at one time or another, just search the forums. I'm not a wiring expert but do have some basic understanding (used to install car stereos as a hobby) and didn't have any problems. The diagrams are great and the 'forum support' even better.

To terminate a wire I traced it back as far as I could, clipped it and used heat shrink.