The Stovebolt Site Forums The Shop Area The Electrical Bay Johnny Cash Re-wire

This is probably going to generate some passionate responses, but I’ll ask anyway.

My truck needs a re-wire at some point. It’s mostly original stuff, converted to 12v decades ago, with some cobbling by the original owner for additional and accessories and a handful of fixes by yours truly to make things work.

The trucks now runs and drives, and I’m tempted to just start re-wiring it myself “one wire at a time.” That seems more attractive to me than ripping everything out and buying a harness. I can bite it off in manageable chunks and do it an hour here and there as I have time.

It wouldn’t be haphazard or half-arse. Just plan one circuit or system at a time, choose the appropriate wire gauge/color, correct issues I find, etc. For instance, maybe start with the ignition/ charging circuit. Set it up, test it, remove the old wires, and temporarily zip tie in place until everything is in place to loom nice and pretty.

Anyone done something like this?

Yes, that's the way I did it. I bought a fuse panel and mounted it on the inside of the firewall left of the steering column. Make a list of circuits and tick them off as done as you go along. Get a decent ratcheting connector crimping tool. Use heat shrink tubing on soldered splices.

Yes but not on this truck. Did a 1966 Mustang this way but I realized doing a complete harness probably would have been faster.

There are so few circuits on a truck like this that even if you buy a ready made harness it can be done in a couple days.

What is there?

Starter
Generator
Headlights
Brake Lights
Taillights
Horn
Heater
Instrument cluster

That's the only way I've ever approached a rewire job. Somebody halfway across the country (or around the world) can't be nearly as accurate as I can "one wire at a time" on a specific vehicle. I can also come up with special circuits and/or wire sizes and fuse panels or circuit breakers to suit my specific needs. Of course, doing, and teaching automotive electricity since the mid-1960's might have just a little influence on that opinion!
Jerry

Did you fuse quite a few things that weren’t originally fused circuits?

I purchased a quality rewire kit with all the harnesses and connectors. Everything was well marked and fitted. That worked well for me (I do have custom wiring also).
don

All the advice is right on.
1. One wire at a time is preferred by some.
2. A harness kit is preferred by others.
3. Both end up being one wire at a time. One is actually installing one wire at a time, the other is hooking up one at a time. You do it in sections as spelled out by Otto and as you yourself said.
4. I prefer a harness kit. The universal prewired fuse box type. You don't want an "original" harness unless you are a purest.
5. You want everything to be fused.
6. Good time to convert to alternator if not already done. There are a few other "tidy-ups"/changes also.

I have done lots of wiring with a harness and one time without.

The prewired fuse box harness will not be more expensive than one wire at a time, Most likely you will spend more money buying pieces. You will have to buy EVERYTHING. No instructions, no connectors, no wire markings. You will have to buy terminals and contacts in bulk possibly. You won't be able to buy any of the "original" colors. The harnesses will have the more modern era Chevy colors.

The harness kits all have the same quality wire. You don't have many circuits/wires as said.

Post again if you need help in buying a harness. I have found that a harness is less work and a cleaner install. I will say that I have always removed the old wiring first. Keeping it in a sort of "harness" and putting it away for reference. Don't throw anything away. Take some pics before removal. As said, it is not a huge task and nothing to be worried about. We will help.

Yeah, I already figured it would cost me more money to do it this way. I’m not a stickler for originality but would like to at least route it in a somewhat-original way. Hide the upgrades to the extent possible. Already have some ideas there. I do plan to keep the generator for now.

Main motivation is just my work style and life. I’m might find an an hour or two in the garage and tackle, say….the instrument panel….one evening. And then I can button things up and the truck is still drivable If I don’t get back to it for a month.

But I’d be pretty hard pressed to find an entire free weekend to do the whole truck.

I did mine one wire at a time about 9 years ago using a 10 position terminal board and 5 relays with fuses. Very happy except if I had it to do over I would have put both the terminal board and the relays high on the engine side of the firewall where I could reach them instead of up under the dash where my fat 75 year old 6'5" tall body doesn't want to go anymore.

One thing to look out for in a new wiring harness.

The common modern mass produced wiring harness is made (wire sized) for 12 volts, V8 engine and a 70's to 80's style steering column. The kit will be plug compatible to some modern conveniences but if you want to keep your old steering column and clamp-on turn signals, you will have to purchase the mating plug parts separately and figure out the wiring yourself.

For the older trucks I just hard wire the turn signal. No problem. If a person wants a connector, Just use the one supplied in the kit.

I do understand you want to wire it Johnny Cash style. So harness kit talk is not relevant. I will switch to your preference. Let us know how it turns out.

Restating what I tried to say before about a kit. The turnsignal/emergency flasher/horn/etc. connector wiring is a prewired sub-harness that plugs into the donor GM or new purchase steering column. There may not be a kit supplied opposite gender plug, pins and wiring to adapt a conventional steering column. This would be extra cost to the manufacturer and higher kit cost. Cutting wires at the connector and hardwiring to old wiring is also an option. The reason for even mentioning it is that this is just one example that shows the need for a person to do their "homework" first. The kit instructions may not cover everything you need to know for your application.

Kent "Lightholder's Dad" brought up an interesting idea in a past discussion. A young person will not have an issue contorting their body to do wiring work underneath the dash. Older guys like me find it painful. Kent's idea as follows:

You can reduce the amount of time spent under the dash is you remove the light switch, speedometer and gauge cluster. Pull the harness through the firewall with extra towards the cab. This way you can attach all those connections to the light switch and dash gauges in comfort inside the cab with good vision. Then install the items back into the dash. I learned it is easy to install the speedometer and gauge cluster just sitting in the seat and installing the mounting nuts with a 3/8" socket and driver by feel. There are several old threads on this subject in the forums. Now just pull the harness taut into the engine compartment.
Kent

I agree but the under dash wiring needs to be bundled and tie-wrapped (cable tie) or run through a split wire loom.

You are right buoymaker. As an example.....the speedway 12 circuit harness at $186 would need a column connector kit at $10. Most of which you would not use, Just the mater to one of the included column connectors. Both items would be free ship. I could not find just the mate being sold. Of course, any 7/8 pin connector pair can be used or hard wire.

You and Kent are right. I've done a lot of wiring sitting in the seat and a lot with the seat out. Thankfully not much to do on a 51. I've only done TF and up....and other brands of trucks/cars. In general, switches are wired hanging, then installed in dash. Gauges may be mostly mechanical. I usually wire of gauges on my lap with steering wheel removed. Some of this depends on the vehicle. Doing a 1957 Willys truck right now.

I did one wire at a time on my ‘52 and with the price of wire today you will save money and time by buying a harness. I went to many FLAPS trying to find the right color in the right gauge and length, not to mention boxes and boxes of terminals. I would be half way thru a circuit and find I didn’t have the right connector or I ran out of wire, so off the the FLAPS again. Most FLAPS don’t carry a big selection of colors, so most of my wiring is black and red (no color coding).

If I had to do it all over, I would buy the harness.

In case you want to buy a plug and play harness,

YNZ Yesterday's Parts Complete reproduction wiring harness for all makes and models
http://www.ynzyesterdaysparts.com/
909-798-1498


Rhode Island Wiring Service, Inc. Wiring harnesses for all years, all makes and models
567 Liberty Lane, PO Box 434
West Kingston, RI 02892
(401) 789-1955
http://www.riwire.com/

I’m open to suggestions on wiring harnesses and heating people’s experiences. Leaning heavily to doing it myself, but haven’t bought anything.

Quite a bit of extra (but period) stuff on this truck which makes me lean away from the resto harness, and adapting a universal harness sounds like a headache. But I’m here to learn.

Things on my truck which are not necessarily stock per the 51 shop manual wiring diagram :
* 12v conversion with ballast resistor
* spot light
* cab/ chicken lights
* original radio
* heater with fan
* turn signals (park light dual filament, separate fixture in rear)
* horn mounted on firewall with period-type relay.

I intend to keep all that stuff in its current configuration.

Even if you do a rewire one at a time, you are going to want to install fuses which are not original to the truck, but improves safety tremendously and is a must do in my opinion. In my case I added in line fuses which you can do, by it looks out of place. A fuse box under the dash or mounted on the firewall (for easier wiring) would tidy it up. although I have never used a universal wiring harness, I understand that every wire is labeled as to where it goes so it should not be such a headache.

One if our fellow ‘bolters ”bartamos”, is an expert in installing these kits and has posted in this thread. I’m sure he can give you the lowdown on the installation.

Thinking about the DIY route….

If you were going to fuse “everything” or nearly everything….would you set up one panel for “key on” and one for “constant power” stuff? Lots of ways to skin the cat I’m sure.

Yes, that is what I would do. Some stuff like lights, horn and blinkers should be un-switched (constant power) and others like a heater should be switched.

I am using an alternator now so the voltage regulator is gone. In its place is a key-on fuse box using modern type fuses (since if you are out east of nowhere you won't find the old style fuses). It is roughly the same size as the old voltage regulator and allows you to fuse-protect 12 items. There is another smaller modern fuse box for constant power items. Yes, many ways to skin the cat. I would have one fuse box for key on and one for constant power. And if you have things like radiator fan, please remember to use solenoids. Also HEI. A solenoid is helpful there. Especially if you have the original ignition switch. Part of this answer probably should ask "how much do you expect to drive your pickup?"

Around 1976 I created a new wiring harness for a 1951 GMC using the wiring diagram and the old harness (for lengths, etc). In that one the harness was pretty well shot from age and weather. It wasn't difficult...took me a couple of evenings and worked great...but as I said I've done this work before. And in 1976 you could find all colors of wire in all gauges. But I found it handy to use small pieces of masking tape to identify things like which side of the fuel gauge, etc. There really isn't that much to worry about on these, you know. Sort of like a VW beetle. You can rewire one of those in an afternoon (aside from the courtesy light wire). Good luck. If I was going to recreate a harness today, I think I'd do the work a section at a time. And I'd remove the speedometer. Makes it a lot easier to reach in there rather than to twist around and under. Good luck.

I can buy a 6 or 8 or 10 color wire assortment in a whatever gauge I choose for a pretty decent price. To keep things simple, I was thinking 8 or so colors of 16 gauge. That would be overkill for some circuits but keeps from a ordering a bunch of different sizes.

For the larger wires on the factory diagram, would 12 gauge suffice? My understanding is that larger wire was necessary in a 6v system. Other than the battery cables, it looks like the largest original wires were 10 gauge.

Having done a factory cloth harness rewire of and old a Sprite, and Painless kit rewires of a couple of other cars and race cars, as others have said the organization provided by a pre made was a HUGE brain saver, but all these were done on new installs, not a ‘need to run’ vehicle.
It is also a fact that any pre made likely might need modification.

While I can’t see loose wire build really coming out any cheaper at the end of the line, one thing you might consider is that a well chosen pre made harness has most of the crimping completed and fuse box connections predone and that is at a quality level worth considering since factory crimps and connections are difficult to reproduce outside a production setting.. that and the fact that the main runs are pre bundled and wrapped, which is also difficult to reproduce in the field and after the fact.

In any case do hunt down a very high quality crimp tool and the finest of crimp on fittings…….which local FLAPS around here just don’t sell.

I used a fuse box with 6 fuses. I used all 6 of them, so an 8 fuse box would be better to provide a couple for future use. The old wiring had inline fuses for the heater and signals, so these are now in the fuse box. Courtesy lights (dome light) are on a separate fuse from the instrument lights.

I used "trailer" light wire for the rear lights. This is the 16 ga wire you buy where 4 wires are stuck together in one loom. Convenient for securing to the frame. Gives you right, left, running and backup lights.

You don't have anything on your truck that is difficult to wire or "odd ball".

As I said:
1. We will help you.
2. Don't worry so much.

You don't need a special harness. As a suggestion, the 22 or the 12 circuit
Here will work. After you decide on what direction to go, We WILL help you get it wired. I will go over the basic steps IF/when you get a harness, tell me which one and what part number of the harness. Be sure you buy from a known vendor.
Like Speedway or Summit or Jegs or Classic Trucks, Painless................ In my opinion, the universal type works. They have provisions for alternator or generator. All the rest is cake.

It seems you have not made a decision about harness kit or not. It seems you need this truck to be operable. I'm not used to that. If it can't be parked while you install the harness, then some other method would be needed. I really don't recommend the J.Cash method. Even an experienced DIY person (like me) will take 3 days or more. A shop would be faster. Either way you will run into issues with older sockets, terminal blocks, gauges, clips, clamps, switches and crimping that slow you down. It supposed to be fun, not a hurry up job.

P.S. Some of the questions you are starting to ask tells me you need a prewired fuse panel type. As several guys a telling you, a lot of the work is done, wire is correct for the 12V circuits, colors, labels, instructions, pre bundled for front, dash, rear, motor....... all the terminals and etc. You need wait until you can schedule this job.

I don’t NEED the truck to be operable. But it’s taken it’s first ventures on public roads in the last few weeks and the family is actually enjoying it…..rather than the punch-line it’s been just sitting in the garage all these years.

Everything that needs to work, works. Lights, signals, charging. Good enough to take it to town once a week and cruise around.

I completely agree that the universal harness is the sensible way to go for most folks. But I’m still about 80% in the J Cash camp at the moment. One of two things will happen if I go the harness route. I will either:

1) Buy the harness and the harness will sit untouched for 6 months
2) Rip out the existing stuff and the whole truck will sit for 6 months untouched

Life is busy with 4 kids and one of my personal weaknesses is dreaming bigger than time will ever allow. Also too many competing priorities and other hobbies besides old trucks.

However, I can buy 25 feet of 4 color trailer wire (as you have suggested in the past) for very little money and knock out the entire rear of the truck when I get a random Sunday afternoon that’s otherwise uncommitted. You actually helped me get my signals going not too long ago. I have a good grasp of what needs to happen there. This way, the truck never misses a beat and if my daughter wants me to take the truck for ice cream the next weekend….it’s still there to use.

I don’t mind asking dumb questions and learning as I go. It’s fun. I actually enjoy crimping terminals and applying heat shrink….an oddly satisfying task. I don’t mind that it will take 3x as many hours to piece meal this job as it would to schedule the time and just blitz it. The journey is as good as the destination on these jobs for me.

Well said. You have to fit your lifestyle

What kind do you prefer? I really really hate the ones with the plastic covers on them.

I like non insulated crimp on connectors, then I cover them with heat shrink. I prefer using the waterproof type so it seals out any moisture. Thomas & Betts or Sta Kon are one of the best crimp on connectors and I’m sure there are others. Stay away from those boxes that contain 200 or more assorted connectors (eBay or Amazon) as they come from China and are thin and much more prone for failure. A good crimping tool is a must. Ratcheting style is great but they can be expensive I have a Kline hand crimper that has served me well for many years. Don’t buy a cheap crimper. It will give you poor crimps and drive you crazy.

Just my cents!

Crimped connections are best. Soldered connections have issues down the road, even if they look really nice. This is why you don’t solder connections in aircraft- they are all crimped terminals.

I bought an American Autowire kit for my ‘50 pickup and was pleased with everything except the switches they included- headlamp, ignition and brake switches were all later model GM and using them would have required enlarging the headlamp switch hole in the dash, etc… although it was advertised as a kit for my specific year truck, it was designed to cover trucks well into the late 60’s. The wiring coming out of the fuse box wasn’t thought out very well, and I think that laying one wire at a time would have resulted in a much nicer looking harness.

As far as swapping out the steering column, I think that would kill the whole vintage look and feel of the truck- nothing wrong with doing that, but it takes it further away from being a classic, I think…

I’m not sure how you would do one wire at a time while continuing to drive the truck, unless you are willing to keep the substandard fuse layout though (or install several fuse blocks, one at a time)…. Also, in-line fuses are a nightmare when you have to troubleshoot something down the road- I would not recommend the in-line fuse route.

I’d like to hear ideas about upgrading the fuse setup while driving it and wiring it one wire at a time… this will be an interesting challenge.

Things must have changed in the aircraft industry- - - - -USAF combat planes had thousands of soldered connections, especially the B-52's I worked on with over 100 miles of wire on each plane.
Jerry

Lots of solder connections in aircraft and space vehicles. Crimp also used. Other solderless, non crimp terminations used.

As far as crimping contacts for our old trucks. No problem. Soldering is not necessary. Not advisable.

Ratcheting crimp tools do nicely, (Kline 3500cr type?)
Soldering? heat control, long term flux corrosion, excess stiffness, etc, outweighs any benefit in my view on our rigs.

I’ve only just begun to think about it, but the best thought I’ve had so far would be mounting the fuse block(s) and getting power distributed to it/them (redundant to the original setup)…..very early in this process. Then start connecting circuits to the fuse panel as I run the new wire to whichever system I’m working on.

A fair bit of forward planning will be necessary. And even then, things will be kind of clumsy with some rework and what not. I’m ok with that.

One of the first items I’d like to tackle, is new wire to the rear of the truck. I might actually do that BEFORE adding a fuse block. Just connect to the existing system and leave myself enough wire somewhere that I can reconfigure later as necessary.

I’ve also considered a “hybrid” approach. Buy a universal harness to source the wire and fuse panel for a reasonable cost, but then disassemble it, keep it organized, and still do my Cash-style re-wire over a period of time.

For the “built my own” wiring harness crowd….

If you added a fuse block, how did you handle the individual components that are switched from the AD light switch. Just fuse the constant 12v that powers the switch? Or did you also fuse the individual circuits the switch feeds?

I've rewired trucks both ways. The "stock"-ish harness was fairly easy to install and required, since most of the original wiring was gone, burned or worn.

I got about $300 into a $200 rewire by running everything separately. It worked just as well as the pre-fabbed harness, but did not look as pretty.

I’ve done a fair bit of thinking about this and studied wiring diagrams both for my truck and some later ones from the 50s. Here’s the tentative plan for now, but it will probably be several weeks before I start the job:

1) Utilize stock-ish 1951 routing but use “1954 and later” wiring color scheme and wire gauge. Have a couple different avenues to source the wire, that I will decide on later. Going to use GM color scheme within reason. Probably have to deviate at a few points to avoid purchasing a million kinds of wire.

2) For the rear of the truck, just going to use some 4 color trailer wire I’ve already purchased. That piece of the job is pretty discrete from the rest and the wire was dirt cheap. Kudos to those who have made that suggestion. The rear wiring will almost certainly happen first as the original wire is super sketchy back there.

3) For fuses…probably going to just source two separate, small blocks. One for switched power and one for constant. Probably keep the period horn relay in service and that might be the only relay unless someone here convinces me otherwise.

4) I believe I’ve found a couple decent options for US made, non-insulated terminals that don’t cost a bloody fortune. I hate the plastic insulted terminals. So we will go nice and slow with crimps and heat shrink.

5). Utilize some sort of braided split loom that looks halfway period-ish. I don’t much care for the plastic stuff that looks like gutter drain.

I am under no illusion of saving money or time with these choices.

………..

Things I’m still undecided upon and/or need input: (All input is welcome, as this is still just a half baked plan).

1) Mounting location/ method - was thinking probably high on the passenger kick panel so as to be out of sight but still reasonably accessible?

2) Constant/battery power - Had anyone incorporated some sort of main breaker or mega-fuse or some such thing? If so, where?

3) Firewall and other body grommets - just use a general purpose assortment? Are there any places where the repop vendors have something that is uniquely useful.

4) Type/placement of voltage reducers. The one currently under dash is the ginormous ugly type.

5) Some of the fuse block options have dedicated ground studs. Would that be handy or necessary?

Mounting location??? If I had to do mine over, I'd mount all fuses and relays high on the engine side of the firewall. Makes it a lot easier than trying to get my fat, 75 year old, 6'5" body under the dash.

Main breaker/mega fuse??? I use a 30 or 50 amp (depending on total system power draw), self resetting circuit breaker connected to the battery cable at the starter solenoid/stomp switch before any other electrical devices/wiring gets power. Remember, fuses don't protect the devices, they protect the wiring. Under $10. Looks like this:

Mount it right on the stomp switch?

No, because the mounting holes are not big enough to slide over the stud on the stomp switch. But nearby.