The Stovebolt Site Forums The Shop Area The Electrical Bay Universal wire harness

I bought a speedway 12 circuit wire harness for my 1947 3100. That came without the original harness no wires at all. I been studying the wiring diagram for the truck and the instructions for the harness. I can see a few wires go to the ammeter. On the universal harness, it doesn’t have wires labeled ammeter. In the instructions it shows a gauge with volts powered by a gauge power wire and grounded. I want to use the original gauges and instruments in the dash.
When installing a universal harness what issues can I expect? Will I be able to wire it like the original wire harness.

You have purchased a hot rod style harness. If this is your first Rodeo, you may have a little rough ride. It can be done. BUT, so you know:
The harness is not designed for an ammeter, it is designed for a voltmeter or idiot light. It is not designed for a generator or a voltage regulator, it is designed for an alternator. The kit has a fuse panel, turn signal wires and is not designed for a stomp starter. I am stating all this assuming your truck is original. If it has some updates, I don't know that. The ammeter will be placed in series with the appropriate harness kit wires.

The harness will not have instructions for much of your truck. You will have to change the wiring method to incorporate the fuses. Your 47 has none. This is not a bad thing, you should have fuses.

Explaining all this is a big job. First you need to decide if your are leaving it completely original. Need to decide on 6V or 12V. This is, in fact, the perfect time for 12V, alternator, voltmeter and etc. That is up to you. Just be aware that wires are wires. Don't get fixated on the colors. Your 47 wiring diagram colors don't match the convention that GM settled on anyway. You can try to use the correct colors. Wiring is just a "To-From" Exercise. Your 47 wiring diagram will be followed somewhat with mixing in fusing. That would sort of be a restomod wiring job.The early AD guys will advise. If you get stuck, just post and we will straighten you out on any hook up question.

SO, NO, you can't exactly wire like original wire harness using this harness. The only way to do that is buy some wire and wire it. A 47 harness would be just wires, with terminals for you to crimp on the ends and terminate. This is because of the above stated differences in the old 47 wiring method and the intent and design of the new fused harness.

We CAN get you wired. Just read and respond with your ideas about the direction you want to go. Again 1947 type guys/AD guys will tell you what they did. There are VERY few wires on the 47, that is what will make it easier. Running almost everything thru a fuse panel will not be too difficult if that is what you want. I assume it is because you bought a kit with a fuse panel.

The truck is original, no wire harness though. I did a engine swap installed a 235. So not original anymore. I did buy a kit with a fuse panel. I’m thinking of returning it and buying a replacement ‘47 Alternator harness from classic parts or Jim Carters, they seem simpler to install. I plan to leave it mostly stock with the stomp starter and everything in the dash, but with 12volt and alternator. I have a GM 10si 3 wire alternator and 12 volt starter.
What about using a 47 replacement harness and buying a separate fuse panel?
Sorry for the dumb questions. The only thing I ever wired was a car stereo.

Bomber

Once you decide on a harness it will come with a diagram sheet
You'll need that plus the original diagram from the shop manual to map out your harness

Bart is right, to complicated to describe here

Best to get your ducks in a row.

Once you have it all , draw it out on a sheet of paper with all your components it will come together for you. Its not has difficult as it looks, and once you map it out it will be clearer. Fuse box protection is good idea.


For me it helped to map out each circuit separately.

You have made the wiring much easier with an alternator. You do want a prewired fuse panel harness. The one you have will be just fine.
BE SURE that your 235 is a 12V motor or you may have flywheel/starter gear mismatch. 1955.2 and up 235's are 12V.
Do you have a 12V 235 motor?
Do you have a 12V externally resisted coil?
Do you have a ballast resistor?
Do you know about swapping to 12V bulbs and voltage reducers for gauges?
Do you have a button switch on top of your foot starter that has a "side terminal"?
Are you doing turn signals?
Other than gas gauge and ammeter, do you have any electrical gauges or tell tales? (old word for idiot lights) (technically called annunciator/indicator)

Read the tech tip here on stovebolt re: 12V conversion

Anything I say that conflicts, let me know. I found the instructions and I was wrong, they DO cover the stuff I said they didn't. Ammeter, generator, alternator, ballast resistor..............very impressed and stand corrected. I wrote all that stuff above before I found the instructions. Use the instructions. I read painless website and it said on hot rod harness they don't support those items. (Customer Q&A). These guys do.

Yes, the Speedway harness comes with a very detailed and easy to understand instruction sheets as well as each wire being printed on as to it's destination. We wire an AD in one day (with 12v and alternator) which includes a turn signal switch, dual contact park light sockets, and two tail lights. On a 1950 3100 in the shop right now it will be a two day job since it has a swinging brake pedal and brackets will have to be made for a modern brake light switch. I'd bet on the assembly line in 1950 one was completely wired in under 10 minutes with several workers handling different tasks. The one pictured has four hours time on it today and will be finished by noon tomorrow. If you need instruction sheets PM me and I'll send you some.

[img]https://i.postimg.cc/R38DFWvt/IMG-5016.jpg[/img]

[img]https://i.postimg.cc/PvHKpZ9C/IMG-5017.jpg[/img]

This 1949 3100 is how we like the finished harness to look like.

[img]https://i.postimg.cc/7CWZZnCN/dan-s-49-012.jpg[/img]

The motor did come from a 12 volt 1955.2. I have the 12 volt coil, ignition resistor and the 12 volt conversion starter with a button switch with side terminal. I don’t have a voltage reducers for gauges. I’m missing the gauges,(if anyone has a extra pair laying around I’m looking for some). I know I have to swap out the 6 volt lights for 12 volts. The distributor has this on it i don’t know what it is, and does the red wire coming from distributor go to the + slide of the coil and from the + coil to the side switch on the starter? I’m not sure about turn Signals, did the 47 come with turn Signals? I guess I should.
I have gone over the tech tips on 12v conversion a few time. Still seems complicated, nerve racking.
Are you sure this harness will work?
Will I be able to use the stomp starter, gauges?
I understand 5. it’s just like the 47 wire diagram.
I don’t understand 6. What wire to fuse panel, and where on the fuse panel? That wire normally goes to B on the volt. reg. But we’re not doing that because the alternator is getting installed, correct?
A wire from Ammeter - To ignition switch, ok.
And the 10 gauge to alternator battery stud from the Ammeter - also?
Thanks guy,

Coilover have you guys used this speedway harness at your shop? I bet they did install a wire harness in 10 minutes back then. For me it’ll be 10 years 🤔

Your edit: looks like someone added a Pertronix pseudo HEI. It's a pick off coil instead of points. Some like it , some don't. Leave it for now. Doesn't change anything. Keep them surprises coming.

Turn signals are almost a must. Hand signals don't work at night. It will take converting to dual filament bulbs. You need two lights in front and rear if you don't have them already.

I didn’t see where it covers Ammeter. I saw generator,alternator and ballast resistor. But not For Ammeter. Can you post a link?

The ammeter gets fed direct from the main supply source on the starter 12v terminal, no fuse. Feeds everything else from the other side ammeter terminal, which should go directly to fuse box except for hot wire to headlight switch which has its own breaker or fuse.

When engine is not running, turn on a load, headlights work, if ammeter needle shows negative, correct, if shows positive, switch ammeter terminals.

Ed

Instructions:
Sheet 4, last sentence.
Sheet 10, lower left paragraph titled "IMPORTANT"
Sheet 14, lower right

You need to get put of panic world and get into fun world. You need to want to do this and learn. You have help. We are here as long as you keep answering questions and check your post often. Go slow, read more carefully.
Let me know if you are going to do this or are deciding to have it done. What is your feeling?

Thanks guy for the help.
Bartamos I didn’t know those instructions were available, thank you. I’m going to do this, I have to learn and with your guys help and knowledge I know I can. Today I’ll open the package and bundle the wires, maybe try to map it out. So get ready for a ton of questions. Lol
I really appreciate the help.

Great. Read the entire instructions again. You always pick up little things after you read a few times. I always do. You have the right idea. The only way to begin is to begin. If you don't cut or break anything, it's all re-doable.

It will be necessary before you get too far, to have all the components in place or available. Ignition switch, ballast resistor mounted to outside fire wall, coil, starter, alternator. Need to scope out a good place to mount the fuse panel and how you are going to mount it. (on a bracket or not, etc). You will have lots of questions, no problem, but so will we. NEVER be afraid to ask questions.

What have you decided on turn signals?
Do you have any gauges? Here is the fuel gauge reducer if you get a 6V fuel gauge. You won't need the expensive Runtz type unless you have a radio or heater. Even then, you may not. (use a 12V radio and swap the heater motor to a 12V motor) Easy and smart.

DON'T install the fuel gauge or it's tank sender until you test them, with the voltage reducer, together on the bench!

The only thing I don’t have is gauges. I’m still looking for some. Unless I get a new set of reproduction gauges, kind of expensive though.
I am going to run the turn signals.

I bundled the harness into sections, listed the wires I’m going to use and the wires not going to be used. I haven’t cut any wires yet just rolled them up out of the way for now.
I found a spot on the upper left corner of the firewall to mount the fuse panel. I’ll make a bracket, spot weld it to the firewall and screw the fuse panel to it. That way I won’t have screws poking out the firewall.

Question. When I run the rear section of the harness, tail lights, brake lights exc, Does it go through the inner firewall, down onto the frame rail through the engine compartment?

The front and rear lights bundle goes thru the firewall. Then they split. Rear goes down firewall and into frame rail and on back. Front bundle goes down left fender to left side lights and crosses over radiator support to right side lights. Click on pic to expand. There are lots of pic on the internet. "1947 Chevy truck engine" "1947 chevy truck wiring" etc.

I can’t find any 47 gauges. So I’m thinking of ordering one from Jim Carter’s, He has restored gauges, the question is will I run into any issues if I order a original gauge? Since the original gauge has a 212 temperature and 30Lb oil, I’m running a 1955 235?

1955 235 - what is the engine serial number?:

An early 1955 truck 235 with high-mounted water pump; or, later 1955 235 with low-mounted water pump (which would most likely have 1956 specs)?

In 1956, the 235's thermostat started opening at 157 degrees and was fully open at 183 degrees
6.25 psi to 7.5 psi pressure cap

Engine # 3836233 i think it’s a 56 . It had the low mounted water pump, but I changed it to a 216 high mount with pre 68 Dave’s adapter plate.

Would that be 3836233? (1955-2nd into early 1956)

As asked earlier, what is the Engine Serial Number (the code pressed into the block - in the flat "ledge" to the rear of the distributor)?

Yes it’s 3836233

I don't see any difference in gauges except 56 temp says "C" "H", cold is still "0" on 47 gauge and 220 is definitely hot. The 47 cluster should work just fine.
Two issues to remember:
1. Gas gauge needs a voltage reducer.
2. Need to investigate sending for temp and oil. Mechanical vs. Electrical vs 47 vs 55/56

Was the 55/56 electrical? I know 47 was mechanical. I’ll go look at the engine. After looking at the engine, I don’t know where to look for the oil sending? This is what I see. Is that for temp and electrical?

043443T255XA

043443 = 42443rd truck out of that plant that year (that series?)
T = Tonawanda, NY engine plant
255 = second series 1955 Task Force truck
XA = 3600 (3/4 ton) truck

Someone will correct/clarify if necessary.

Bomber, you need to do more study using the internet, the stovebolt search function, service manuals and assembly manuals. We don't mind helping but you need to put forth some effort on things that are easy to search. We can help on the tuff situations you run into.
1. If it is in the water jacket it's temp, if it's the oil spaces, it's oil pressure. Take it out and see. We can tell you by looking but it's better to try first and figure it out first.
2. Sometimes you can just see what the replacement parts for various parts are being sold by vendors, for various motors and years. You then start to build a knowledge and how to figure things out.
3. If you want to use a 47 gauge cluster, determine if it had mechanical or electrical or both. Then search the Stovebolt using various search words to discover all kinds of guys with the same issues and you will learn more about what sender they bought and etc,
4. I am not discouraging you, I am encouraging you. When I need to figure something out, I search in books and online pictures and all the methods described. If I can't find the answer, I ask here. But I don't expect them to build every inch of my project. It's just good to know how to figure things out.
5. I am only telling you how to proceed with your project and the work you have to do includes research, not a virtual online mechanic. You will be a better builder with those kind of tools also. I'm trying to say this kindly, so if you need help on everything, we do that too.

Probably didn't come across right. FYI: most of the time I answer a question for someone, I HAVE TO LOOK IT UP That's how I learn.

thanks bartamos. I’ll keep searching
Ok I think I got it. I have a electrical temperature sending unit. To make it work with the 47 gauge, I have to install a 1937-1962 temperature sending unit reducing bushing. Which will accept the smaller mechanical heat probe that comes from the 47 gauges.
Oil pressure is mechanical. I didn’t see the tee where the oil filter line connects rear left side of the block.

...and researching

Lol. yup now the oil sending search

Forgot so say if the sender has a "turret top" that's for an electrical connection. If a sender is mechanical it uses pressure, thru a tube all the way to the gauge.

I have been looking at Jim Carter, thinking and searching and researching. Here's what I say. Some of it may be obvious.
1. The sender does not care what oil pressure or water temp it is sensing. It just reports. Temp will be 30 OHM. So "fits" any motor of or near that era. Screw it in the motor where it belongs.
2. I would call Jim Carter and find out what senders are attached to the cluster he sells, if any. If none, ask what sender he has for his cluster. The temp sender tube is permanently attached to gauge. Oil tube is nutted. He sells 47 temp and oil gauges and they have tubes and "sender" probe attached. Hope he includes both with the cluster price.
3. I believe I would use mechanical because the cluster is mechanical in 47.
4. Carter has a oil pressure gauge for low pressure engines at 30LB and high pressure engines at 60LB. This is probably why Tim was asking about numbers on motor. You probably have a high. So when you contact J. Carter ask if can get that gauge in the cluster. There seems to be two 47 temp gauges available, 212 and 220. This is why Tim mentions the cap and thermostat. Carter says the gauge cluster is one year only. That's always nice to hear.
5. The same mechanical temp gauge sender/sensor/probe was used up to 56ish for 6 cylinder. So you are OK there. Mechanical changed to electrical in 55.2 to mid 56. Where the needle reads is up to the cooling system you decide on. Cap, Tstat, fan, pump volume, fan distance and radiator.
6. Carter sells same 4 lb radiator cap for 37-59. Pressure system.
7. You may need this.

Tim Lederman knows a lot about this. I defer to him for any corrections to my above....... and any other experts.
Just giving you some brainstorming ammo.

Bartamos, your links have disappeared. I am putting a painless wiring harness into my 46. The painless gives one wire to the gas guage and one one wire to the ammeter. what do I do with the other poles on each of these gauges? I have the wiring diagram so I know where they went from the factory, but the painless harness runs things through a fuse block?

I don't know which of my links are missing...... but a gas gauge has a hot wire and a sender wire. An ammeter has "all hot wires". I understand you have a 1946 wiring diagram and you have a painless kit. You know what the idea is, but you don't know what painless wires to use. SO........post the exact part number of the painless kit and it's instructions...or a link....and I will check it out.

They supplied you with a (assumed fused) hot wire to the gas gauge. The sender wire is just a wire from sender to gauge. You just do that yourself.
As far as ammeter, there is a battery post and a load post. They have probably supplied the load from the fuse panel. You supply a wire from the battery. I have to see the info. You may have to supply other loads to the load side. You may tap into the battery side to get battery voltage to something. Voltage flows both ways thru the meter. Charge/discharge.

Logic says that if you bought a painless harness, that you are converting to 12V.

Thank you for the help. Attached is a page from the Painless wire instructions for the Instrument panel. I am going to stop trying to get the Ammeter going, and just go with a Voltmeter.

If you look at 2nd paragraph down, the Pink wire is what I am referring to for the gas gauge. The way I understand this, as well as other posts out there, this Pink wire would go to the back of the gauge where the red sticker from the factor says this wire goes to the sender in the tank. What I am missing is a power source, which I could take from the "run" position of the starter switch? I also would have to put a voltage reducer in this wire from the ignition switch as I am converting to 12 volt.

1. If the pink wire is labeled fuel sender then that is what it is.
2. "Power to gauges" should be in the harness? If not, power comes from run. If you look at original posters pic, the red wire says "gauge power" and is chained to all the gauges. looks like it is part of the harness. There is a hint of this in your 3rd paragraph.
3. Voltmeter: good move.

If you need further info: Remember, I asked for harness part number and all instructions and diagrams/schematics.

Thanks so much. Wish I would have thought of that myself. I appreciate your patience and help.

No problem, wiring is scary at first. We are always glad to help a DIY person. Looks like you have quite a collection. Lots of wiring
12V is a good idea. A prewired fuse panel is a must. It's a good time for Alternator. Are you hip to ballast resistor and a new coil, starter side terminal, etc?

Yes, you will need a voltage reducer for an original 6V gas gauge. Don't know why 46 is not included.

I called Jim Carters. they said the 47 gauge would be just fine, he said the 60lb would be for like a V8. I would need the temperature sending unit reducing bushing, Also the oil pressure line kit. Today I got them. For the last week I been going over the harness instructions and the 47 wiring diagram, google searches on the site. Still I can’t figure it out.

On the harness it says to rout the 10 gauge solenoid power wire from fuse panel to ammeter, and from the other post on ammeter out to positive battery source. but doesn’t say to what post from the fuse panel (C+positive or D-negative) on the ammeter?

On the 47 diagram it shows 1 side of the ammeter goes to the last terminal on the fuse block and a wire to the starter or battery.
I’m guessing that would be the positive battery source. In the harness instructions?10 gauge coming out of the ammeter.
the other post it shows a wire from ammeter to ignition switch and to the b on volt,regulator.
And that’s confusing me.
After doing searches it gets me more confused because some say it doesn’t mater just to switch the wires around and some say there is a neg- and pos+ side. Thanks for the help

I would hook the battery source to the terminal on the other side of the Amp gauge face discharge.
The 10GA to the terminal on the other side of the gauge face charge.
At some point you can turn on the headlights without starting motor. If the meter goes to discharge it's correct. If it goes to charge it's backwards. Ammeter will flow current either direction.
You can also use a flashlight battery, etc. Put the gauge in series with a 12V bulb.
Battery to one ammeter terminal, other ammeter terminal to bulb contact, bulb case (neg) to battery neg. Should show discharge if you have selected the correct ammeter terminals.

Thanks bartamos, So I would run the 10GA from fuse panel to the gauge face charge post along with a wire to the ignition switch and a wire to headlight switch and the battery source from the other post going to the starter with a fusible link? Sorry if I don’t understand and I repeat what you say,it’s all new to me, I’m trying to learn.

Yes I think you said it correctly. The confusing part of all these Harness Ammeter instructions is they call the fuse panel wire the "Solenoid Power" wire. But the other battery power source wire is obtained from the solenoid hot stud/battery cable stud. At any rate ......... One ammeter terminal is the load side. Everything is on that side. The other terminal is thru a fusible link to battery cable stud on the solenoid.

Sometimes the headlight switch is direct feed. So as far as what you said about headlight switch and ignition switch, I think wiring per harness instructions will get that done correctly. Not necessarily the 47 diagram.