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

Yes, I have worked on older aircraft and there is a lot of solder! The Industry has moves away from that practice, as the FAA has determined that crimped connections are more secure and have a longer life….

JW51 Old rodders would build there wire loom then wrap it with kite string,using a continuous loop system you could unravel,repair then wrap it back up. Today you can use industrial size(1 inch) teflon tape. Nice and clean and dry and easy to remove do repairs then replace.Sticky tape is messy and hard to work,especially cheap tape.

Reviving this thread. Didn’t get very far on this project last year, but it needs done and I’m motivated to get started.

Phase 1 is going to be new wire to the rear of truck and improving the rear light/signal fixtures. I’ve got a roll of nice trailer wire. Need to source a couple things and get some advice here before I tear into it.

My thought is building a pigtail or sub-harness for each side of the rear. Make it somewhat easily disconnect-able from somewhere under the truck near rear of the frame.

1) Recommendation on connectors if I do the pigtail approach? I’ve looked at waterproof bullet connectors, and also the Delphi-style weather pack connectors. (I’m trying to give a nod to period-correct where things can be seen, but don’t mind using modern tech out of sight). Some other type of connector?

2) Skip the pigtail approach altogether and just wire the whole rear as continuous? (Understand will need some branching/splicing near rear of truck)

I'd wire it with as few connections as possible. Those are just potential corrosion points. Unless you have definite plans to disassemble the tuck in the future, what reason could there be for pigtails and bullet connectors?

Think about other cars you own. How often do you need to disconnect the wiring on any of them?

Leave a little slack in all your wiring to enable adding connectors later if you ever have to take it apart - to repair crash damage, for example.

Future leaning thought #1: I’m starting to get a better idea what I want to do for fuse blocks and such. Probably going to add a relay or 2 and make kind of a custom panel to mount it all up.

Would like to get some thoughts on location - I want it ask out of sight as possible, and also minimize standing on my head when I want to work on something or add a circuit or what not. Achieving both of those at the same time will be a trick.

Ideas:

* Not interested in mounting in engine bay.

* Locate fuse/relay panel high on drivers side kick panel or firewall. This achieves the out of sight goal and lines up well with where much of the wiring exits the cab. Makes access a pain.

* Locate said panel beneath radio speaker facing down. Make some sort of black enclosure so it’s fairly inconspicuous. Not ideal for making it unseen or easy access. But not horrible for either of those goals.

* Modify glove box or mount under glove box. Truck has what appears to be original glove box interior. I’d rather not screw with it.

* Mount high on passenger inner firewall. This is probably my current favorite but has its own downsides. Way way less crap in the way than the driver side. Could be tucked up kinda high and still be fairly accessible. Downside is that it’s a long way from most of the trucks circuitry. Extra wire will be involved if I want wire to exit the cab in the original-ish location.

Let me know why you think. Just for context on space/size, thinking I’d probably doing a six-ish fuse box for constant, and an another one dedicated to switched power. 2-4 Bosch style relays. Will have to link a pic or video of something similar for you to envision how much space this will occupy.

I did mine with 5 Bosch style relays (one is a spare) and a 5 position fuse box in the middle of the inside of the firewall. I have A/C, so the right side and glove box are no-gos. Given the A/C, an underdash radio and way too many calories per day into my 6'5" 76 year old body, I wish I had installed it under the hood, high up on the firewall.

I didn't know about these combination fuse/relays when I built my electrical system, but if I do it again I'd use them. The only thing "wrong" with these relays is there is no "normally closed" contact (87a), but I've never needed this in automotive wiring.

I’ve seen those fused relays, but wasn’t sure which “side” of the relay was protected by the fuse, nor really heard any experiences from anyone who’s used them.

Curious - what all did you wire through relays on your truck? I was thinking definitely headlights and horn (although I might opt to use the old school firewall mounted one. Not sure what else. But would like to design the panel in such a way that I have future options.

Power connects to fuse which connects to pin 30 of the relay. I've used two of the fused relays on a friends car. Worked well so far.

I've attached the drawing that I made that covers the area around the fuse and relay part of my homemade wiring system. It does not show Vintage Air A/C (which has two relays), ignition, lighting (including relays for headlights), horn, etc.

Need to start thinking about voltage reducers for the gauges. Truck was already converted to 12v, but has one big ugly resistor under the dash and what appears to be a ballast resistor on the cowl vent brace performing reducer duty.

I’d like to update the stuff and do it right.

What type should I use? The Runtz ones?

Runtz work good for the gas gauge (and electric temp and oil pressure if you have them). Others on this board say changing from 6v to 12v on the gas gauge requires No reduced voltage, but that once you do it you can't change back.

Original 1951 oil pressure and temp are mechanical, I think?

If I’m right, the only other things besides fuel gauge that might need reducers would be blower motor and perhaps radio? Radio has never worked, but I’ve never really tried to mess with it, either.

Correct. Oil pressure used a small diameter tube to the gauge and the temp gauge is a sealed unit with a remote bulb that mounts in a hole in the head.

Runtz would not supply enough power for the heater blower motor. Maybe not enough for the radio either.

If you don’t like the contortions of working the original location why not mount the fuse block on a hinged or pin mounted panel at/near the drivers foot box location?
Swing it out to build & service it, if you route the bundle of wires to it from the hinge side there will be little or no wire slack to account for…..
Just a thought……
Chuck

What would be the preferred type for those devices?

Maybe dumb question, but it has been bothering me...

What does Johnny Cash have to do with this subject? I know there must be an analogy in there somewhere but I can't figure it out.

You've never heard Johhny Cash's song then.
www.youtube.com/watch?v=uErKI0zWgjg

I don't recall having heard that one before. I like it!

For what it’s worth, when I floated this “one piece at a time” idea last summer…it was with the idea of not taking the truck off the road for an extended period.

I still don’t want to take the truck off the road for an extended period, and I probably will bite this off in pieces, but they will be pretty big pieces.

I can re-wire the whole rear independently, leave some extra wire in play to account for routing that might change at the cab. Prep the fuse panel and mounting. Perhaps wire the front lights back to the junction block as a sub assembly. Have a big “cutover” day/week where the main power gets changed over and wires get routed to the new fuse panels and such.

Just make sure you obsessively label *every* wire in that process. You don't want to get to changeover day and have to go re-trace something you routed 2 months earlier.

Agreed. Some label makers can handle heat shrink.

I probably won’t invest in one, but I have discovered a redneck work-around. If you write in sharp point pen on white heat shrink, you end up with a readable label.

Starting to think through wire routing so I can get wire ordered in proper gauge/length/color.

I’m probably going to relay the headlights. One Bosch style per side, which would mean outputs from the dimmer switch would become just a relay trigger.

The stock dimmer switch puts the output contacts outside the truck. Not a big deal to route them back inside, but then I got to thinking.

Would the slightly later style switch with the terminals inside the vehicle be an option? I’m 100% sure it could be made to work…what I’m wondering is how direct a swap it is. If the existing bolt holes match up, and the foot print of the switch more or less covers the existing hole….I’d probably do it.

But I’m not so married to this idea that I want to go modifying the floor board.

The relays should be wired one for hi beams and the other for low. I mounted mounted mine on the firewall.

I'd just use 12 gauge for everything.

The advantage of the wires on the switch being on the engine side of the firewall is that that's where they're going anyway. Why plug a hole in the floor for the switch and then have to route the wires back out there?

Yes that’s how I planned to do it. When I said, “side”, I meant side of the dimmer output. One for high and one for low beam.

Curious - is that white connector on the firewall just a disconnect or is it an inline fuse?

Nice job of dressing the wiring Phil.

I think there's a glass Buss type fuse in there. My '56 Cadillac has similar fuses on the turn signals.

On the topic of inline fusing….need some input on where to put fuses or breakers in regards to main power distribution and charging system. I’m probably going to take the fuse or breaker approach, rather than the fusible link.

I’d like to simplify as much as possible, but the way this works in my head, it seems like there is redundancy. Wondering if some of the fusing below could be eliminated.

1) Protection between battery connection at starter and the line to the ammeter - seems like there was a strong consensus to protect this circuit.

2) Protection between Regulator and Ammeter?

3) Protection between Ammeter and power supplied to Ignition switch?

4) Protection between Ammeter and new fuse panel dedicated to “constant” power

5) Protection between Ignition switch and new fuse panel dedicated to “switched” power?

Just a thought:

Fuses protect wiring, not the components at the end of the wire. So when installing fuses, place them as near to the power source as reasonably possible.

I did know about the “fuse protects wire” thing. I had not given much thought to “which end” of the wire being a consideration.

Is it fair to think of the entire run from starter to BATT on the regulator as one run? The ammeter itself just happens to be part of the run? Protect it in one spot and call it good?

Then just whatever runs need to branch off to

Someone earlier in the thread, maybe Bill, said they have a circuit breaker not far from the starter. That would be my favored approach.

The phrase "the fuse protects the wire" is true-ish, but kind of misses the point.

A wire of a given size can carry so much power before it heats up, melts its insulation, and starts a fire. The exact math of that is tricky because insulation type, environment temperature, airflow, wire material/form, and a variety of other factors play into the final numbers.

In the case of cars, you can get a table online that shows the safe current for a given wire size. If your fuse is larger than the safe value, then the wire itself will become the fuse and you risk electrical fires.

You can *also* spec your fuse size to protect whatever is on the circuit, as long as you stay below that safe value.

As a rule of thumb, the fuse should be as close to the battery/alternator as feasible because if you get a short between the fuse and the battery you won't have any protection.

Here is a good reference for automotive wire sizes.

Yes, although that run also feeds all other electric loads in your truck except the starter. Mine now has a 50 amp self-resetting circuit breaker mounted a couple of inches of #10 wire from the stomp starter switch and then additional #10 going to the ammeter. As the wiring fans out to various loads through smaller wires, additional fuses are used to protect these smaller wires.

Does it matter from which “side” of the ammeter (regulator or starter) power is pulled to run accessories and fuse panel?

Yes. 50-51 Chev Truck wiring diagram shows the only thing attached to the + side of the ammeter is the 10 gauge wire from the lug on the stomp starter switch and the 14 gauge wire feeding the horn.

Yes, I see the same. Do the + / - indications on the wiring diagram respond to charge/discharge on the ammeter? The diagram looks kinda backwards to me, but I don’t have the truck in front of me to compare.

Sorry, I don't know. My truck no longer has an ammeter.

Wire is ordered, had a question about where I got it. Look for a seller called “brussellex” on eBay. One of my sellers with assortments of GXL or TXL wire. But they let you choose colors. I wanted a lot of colors, but didn’t need a lot of length in every color. So with some figuring, I was able to skinny up the order quite a bit. Curious what others pay for wire from other sources.

I will be using trailer wire for the rear signals. Got a ridiculously good deal on a 25 ft roll last year. I think it’s 16 gauge and I paid something like $6 for it. It was Walmart.com, I believe.

A good part of the spend on this project is strategically using some gift cards I have. Sourced a Bussmann universal panel for cheap on eBay. My eBay money is now spent, so will piece meal the rest between Amazon and O’Reilly. Need another fuse block, some circuit protection for the main power, and a few odds and ends.

If you split the +12 and the IGN at the input to the fuse block, you can get 50A+ maxi fuses to protect each side independently. I think the housings I used were weatherpaks and it let me put 2 fuses in one weatherproof housing with a little cover.

If you are interested, I can pull my records and see what part numbers I used.

Looks like these are the fuse holders I used. I got them from Waytek but they are cheaper on Amazon right now:
30A-80A Fuse Holder

Definitely interested. Thanks. Would be nice so see what someone else has done.

So many ways to skin this particular cat. Maxi fuses, circuit breakers, resettable circuit breakers, etc.

30A-80A Fuse Holder

Moving this down to a new response since your didn't load for me before I made the edit above.

I have had better success with fuses than circuit breakers in automotive systems. I know people who swear by the thermal breakers, but I had problems with them tripping from vibration or bumps and gave up on them.