Cummins 4BT & Diesel Conversions Forums banner

1 - 19 of 19 Posts

·
Registered
Joined
·
235 Posts
Discussion Starter · #1 · (Edited)
When I bought my donor vehicle (72 Wagoneer) every bit of wire in the rig was removed. Along with the dash, interior, front clip, etc. The original 72 Jeep wiring system was based on all "in-line" fuses and very simple (and dangerous). The Full Size Jeep forum guys say it's not a matter of if, but when there's an electrical fire with the original wire harness.

On my first attempt at wiring this up I decided to buy a 91 Cherokee fuse box and use that package to adapt to the Wagoneer. Everything was going fine until I started breaking the plastic retainers that hold the wires into the back of the fuse box. Also, the little metal crimp connectors they used are not all the same. There's about 6-8 different ones, and the bus bars built into the fuse box are fixed and not all in a row. I had to buy a 2nd fuse box just for parts to try and replace all the broken clips. I've been driving it for a year with half the circuits complete and a rats nest of wires under the dash and in the engine compartment. I could finish the route I was heading, but it would just be more that I'd have to undo when I make it right. So I've been driving without dash lights or a dash switch for the heater fan. I have a household (inline fused) light switch under the dash so I have at least a defroster. It's super janky.

I was also doing the wiring one circuit at a time, so a lot of my runs were redundant, I wanted a dedicated ground for every circuit, a relay for anything over 5 amps and very limited power going through the firewall. Right now it's just signal wires and enough juice to power relay signals. I was using whatever wire I had from the two ebay Cherokee boxes so the wire colors don't make sense, and when they weren't long enough they'd change colors with a solder or crimp connector. I didn't have unified plan in mind

Adding to the complication of doing this at all is the fact that I have all these little converter boxes and adapters because this is a Frankenstein rig. Metric Isuzu motor, metric GM tranny, etc. etc. I have a dakota digital converter for the tachometer, another little brain box to convert my custom fuel tank level sender into something a 1972 dashboard can make sense of. I also want to use all the original dash switches and gauges work like it's original.

There is no kit for this. Not even close.

I know people do this all the time and say it's no big deal. I'm finding it overwhelming, and I'm writing several different documents:
A. Schematic (like relay diagrams, wire color, labeling method)
B. Diagram (where wires run)
C. Technical Data (spreadsheet - wire size, length, amp load, and fuse/relay size)
D. BOM (Bill of Materials, Parts list, vendors, costs.)
E. Mission Statement (Rules, safety, SOPs, tools to use, etc.)
F. Futures (AC, winch, compressor, Aux fuel pump, lights, inverter, etc)

That's enough of an intro. I'm going to document my progress here for your entertainment and open to suggestions as long as the suggestion is not "take it to a professional and pay them to do it right."
These pictures are embarrassing to post, but it's the truth and where I am now.

Cheers,
Kevin


 

·
Registered
Joined
·
19 Posts
They have a pretty good wiring kit. Its what i went with my build comes with a detailed booklet with your wiring harness ,wires are all labeled and sectioned into groups
engine bay ,interior/dash to rear light group

My first time wiring and i was able to knock it out in a week
 

·
Registered
Joined
·
235 Posts
Discussion Starter · #4 ·
First hurdle accomplished.
Instead of 27 different colored wire spools with 3 different gauges, I'm going to just buy a couple gauges in Black (-) and Red (+), then some 22g in Blue for signal wires.
Then I'm going to use labeled shrink wrap on the ends. I didn't even have to hack my labeler to work with an off-brand shrinkwrap cartridge from Amazon. I got a 3-pack for $22.
Again, I need to plan ahead on my numbering system so 5 years from now I know what in the world I did.
 

·
Registered
Joined
·
235 Posts
Discussion Starter · #5 ·
Thank you for the kit recommendations. I've looked at a lot of them, I even got a painless kit with the donor vehicle (GM TBI kit), but they don't have enough stuff built in.
I may be crazy... no that's confirmed. But I need at least 8 relays, and probably like 14 when I get done. I would have to add on so much stuff to these kits that I would ruin the simplicity of them and make a mess of it. By the time I have them build me one that I want, I could build it myself for cheaper. I'm probably going to spend less on parts (although 30x the time) than the base kits.

I like to keep things simple and clean, but at the same time I want it to be safe, robust, and redundant. Most of all, I want to be proud of it. And I want to be able to open the hood without telling people to not look at the wiring.

-Kevin
 

·
Registered
Joined
·
235 Posts
Discussion Starter · #6 ·
This is going to be the main block of fuses and relays.

This is where I'm going to buy it:

If you search google imgages on the part number you'll see all sorts of excellent builds that use this type of power distribution block.
 

·
Registered
Joined
·
1,603 Posts
... OK I feel your pain.. I'm terrible at wiring .. SO
Mine is just a suggestion also. Ain't my 1st rodeo . I'm 72 years old .. I owned a Parts Store for 30 years.
I've worked for Chrysler for 10 years & a truck repair for 15. SO I've been around a lot of what your into .
.. MY 1972 Bronco that I put the 4BT Cummins into .. It had to be re-wired completely ..
....................
..... SO THE CHEAPEST & BEST FOR ME ... WAS I went to E-Bay & bought I think it was called an E-Z WIRE HARNESS.
It cost about ... It was set up in 4 sections ...
1. Motor section
2. UNDER DASH SECTION wires for every thing under the dash.
3. HEAD LIGHT SECTION . Side markers fronts , blinkers & Extra lights like more running lights
4TH Was the rear part rear lights . fuel tank wires forward . & of course License plate, back ups. Rear side markers .
....................
...... SO YOU could get a fuse box with about 24 Style ATO FUSES IN IT.. MOST WIRING WAS 14 Ga So wires were larger like 10 I think ..
... THE WIRES were labeled about every foot .. Like left front blinker . Rear Right blinker . & THEN THERE were splenty of the 2 wire trailer connectors . TC23. a STD Ign number & Those hooked onto your tail light .Worked perfect for my Bronco . But you could do Butt splices & solider them ..
& After all that I added a couple more Fuse Junction boxes in line Via maybe a 6 or 8 gauge short wire with Eyelets on each end . & ADDED more lengths of wire.
......................
........ All the wires in that 1st fuze boxes were 20 ft long .& you simply cut to the correct length .
Giving you a nice verity of many colors & stripes of 14 gauge wires for extra stuff.
... I believe when I bought mine it was $230.00
I'm sure it's much higher now.
But maybe this will help you out somewhat.
 

·
Registered
Joined
·
1,603 Posts
I went ahead & posted that because it was getting so long I didn't want to loose it.
But my main points is .. you can get a kit. WITH all new easy to work with wires. & WIRE YOUR JEEP TO. YOUR ..
Rear section is straight forward .Stop turn tail blink.& tape.
Head Lamp section is also rather straight forward .
MOTOR section I don't know which motor you have but . If it's not a jeep motor then any of the stock harness aren't going to help you much. So this kit Is your way to go ..
..... Under the dash WHAT A CLUSTER . DESIGN Your dash to your needs & do away with a bunch of stuff you don't want
 

·
Super Moderator
Joined
·
8,862 Posts
I went through this a few years back with one of my vehicles. It was painful and slow but well worth it in the end. I found about 3 melted wires from historic almost fires in there. I also found a whole heap of bastardry where previous dealers and owners had spliced in wires using whatever colours and sizes they had handy.

I was able to clean up a massive amount of unused wire. Repair all the firewall grommets and now all the warning lights and starter signals do exactly what they should.

My tips:
1. Break it into sub sections which are all loomed and labelled.
2. Buy a heap of wire in the appropriate colours and sizes. Label it all by size and amp rating.
3. Solder seal connectors are fantastic.
4. Add more earths and fused power points now. Run leads to power points that are fused but always live and well as key activated so you have options later.
5. Buy a really nice to use set of crimpers.
6. Use coloured heat-shrink to further identify wires.
7. Move all the relays to one point and stick them in a dedicated fuse-box. I got one off aliexpress that is from some Toyota. It worked great.
8. Diagrams so you can work faster but also retrace your work later. You will not remember all the details.

I've attached a pdf of a diagram that I had to do for my extra relay/fuse box and fan speed control. As you can see it's just not possible to wing-it.
 

Attachments

·
Registered
Joined
·
235 Posts
Discussion Starter · #10 ·
Dougal,
All good points. All things I'm planning on except #4. That's a good idea.
Those hybrid shrink wrap solder butt connectors are awesome. I thought it was a gimmick or they'd be super expensive, but they're just plain sweet.

I've got most of it worked out in my head except where to put connectors and what style connectors. Like, should I put a bulkhead 26+ pin connector on the firewall or run all wires to my central fuse box in the engine compartment? Or put connectors on the fuse box. These are the things I need to work out in my head.

I'd like to be able to take the body off some day and not have to cut a million wires. Same with the motor. I'd like to just unplug stuff and pull the motor. But I also don't want an excessive amount of connectors all around the fuse box that won't tidy up because they're 5" in diameter.

I know it sounds weird, but I really need to set some rules (a mission statement) and stick to it.
 

·
Super Moderator
Joined
·
8,862 Posts
Dougal,
All good points. All things I'm planning on except #4. That's a good idea.
Those hybrid shrink wrap solder butt connectors are awesome. I thought it was a gimmick or they'd be super expensive, but they're just plain sweet.

I've got most of it worked out in my head except where to put connectors and what style connectors. Like, should I put a bulkhead 26+ pin connector on the firewall or run all wires to my central fuse box in the engine compartment? Or put connectors on the fuse box. These are the things I need to work out in my head.

I'd like to be able to take the body off some day and not have to cut a million wires. Same with the motor. I'd like to just unplug stuff and pull the motor. But I also don't want an excessive amount of connectors all around the fuse box that won't tidy up because they're 5" in diameter.

I know it sounds weird, but I really need to set some rules (a mission statement) and stick to it.
I've got the majority of my engine on a (maybe 12 pin) deutsch plug by the thermostat housing. That's oil pressure, water temperature, fan switch and alternator wires (energise, tacho feed) in one loom. The main alternator feed is a single anderson powerpole which connects right beside it and I have three bundled bullet connectors (big and small) for the fans.
So apart from starter wires (hot wire and solenoid feed) and AC clutch which come from the other side it's all in one place that can be unclipped in seconds.

I didn't worry about a big firewall connector. Instead I had looms come through the firewall (maybe 4-5 different places) that are obvious in direction and can be unclipped and laid back. So if you need to disconnect say the gearbox loom (handbrake, reverse and diff-lock light) it all unclips and folds back in one piece with each connector being obvious placement to reconnect later.

Also. Put in feeds for a reversing camera with display.
 

·
Registered
Joined
·
18 Posts
I went through this a few years back with one of my vehicles. It was painful and slow but well worth it in the end. I found about 3 melted wires from historic almost fires in there. I also found a whole heap of bastardry where previous dealers and owners had spliced in wires using whatever colours and sizes they had handy.

I was able to clean up a massive amount of unused wire. Repair all the firewall grommets and now all the warning lights and starter signals do exactly what they should.

My tips:
1. Break it into sub sections which are all loomed and labelled.
2. Buy a heap of wire in the appropriate colours and sizes. Label it all by size and amp rating.
3. Solder seal connectors are fantastic.
4. Add more earths and fused power points now. Run leads to power points that are fused but always live and well as key activated so you have options later.
5. Buy a really nice to use set of crimpers.
6. Use coloured heat-shrink to further identify wires.
7. Move all the relays to one point and stick them in a dedicated fuse-box. I got one off aliexpress that is from some Toyota. It worked great.
8. Diagrams so you can work faster but also retrace your work later. You will not remember all the details.

I've attached a pdf of a diagram that I had to do for my extra relay/fuse box and fan speed control. As you can see it's just not possible to wing-it.
Dougal is right on track as usual. I would add that you should take notice that Dougal is using a program called KiCad to make his electrical drawings. I too am re-wiring my entire truck (Chevy c10) and I too am using KiCad. It is not really meant for this type of work. ( more for designing circuit boards) But it works very well for keeping your drawings organized and broken down into the different systems. Best of all the software is FREE. It's also relatively easy to use. After viewing a few YouTube videos, you'll pick it right up. By the way, for my relay / fuse box, I went shopping at the local junk yard and picked up a nice clean set up for $10. Then I had to make a Chinese blueprint of it, but all that takes is a little time, some tape and some pencil and paper.
 

·
Registered
Joined
·
235 Posts
Discussion Starter · #13 ·
This is exactly the type of help I need. Not how to do it, but more strategy decisions. It's a shame I've taken for granted automotive electrical design. I eagerly digest all mechanical elegance, but have simply ignored electrical stuff. I have new eyes when I look at wiring harnesses now.

I will check out KiCad. I have a full Solidworks suite, but the SWX Electrical seems clunky and not even close to what I need. My 13 yr old daughter showed me Lucidchart which she uses at school so I started some diagrams on that, but it doesn't seem like its meant for this type of work. I had assumed what Dougal was using was not a free software... I'm excited to check it out and thanks so much for the nudge.

At my work we build these huge control boxes (where space is not an issue) with elegant wiring, tons of components; relays, VFDs, micro-controllers, transformers, etc. I'm leaning toward a much smaller box that will fit in the engine bay where I can put all my accessories that are currently looking for a place to live behind the dash. Tranny controller brain, fuel gauge converter, all these little boxes with 4-10 wires that could easily be moved to a safe location under the hood.

Thanks!
-Kevin
 

·
Registered
Joined
·
73 Posts
Had my first run-in with one of those heat-to-solder-&-shrink connectors about 2 months ago. NOT recommended in any area that will see heat. Like under the hood. Nearly lost an engine to over-heating because one of those connectors in the electric fan circuit failed. The under-hood heat was enough to partly disconnect it. I'm not impressed, I'll keep using the crimp and heat to shrink Ancor terminals.

Unless you're going to place those marker heat-shrinks every foot or so I think it's a bad idea to reply on them exclusively. Sometimes you need to know which wire is which in the middle of a long run and if they're all green then which one is the one that you need? (I used green as an example because IH did their Scout II's this way. All green wire with numbers ink marked on them. Which comes off if you happen to use lacquer thinner to clean the loom..... )

Research it because I know that they're out there somewhere, there's a spiffy tool made that allows you to use a Dullie® (that's a Sharpie® after a couple uses) to put a stripe on any wire. I have one that a friend printed. The bonus is that you can use any color Dullie® that will contrast and show up on the base color.

Del City Wire was recently running a special on what looks like it might be a quality crimper that uses interchangeable dies, and that has a wide range of available dies.
 

·
Registered
Joined
·
77 Posts
Had my first run-in with one of those heat-to-solder-&-shrink connectors about 2 months ago. NOT recommended in any area that will see heat. Like under the hood. Nearly lost an engine to over-heating because one of those connectors in the electric fan circuit failed. The under-hood heat was enough to partly disconnect it. I'm not impressed, I'll keep using the crimp and heat to shrink Ancor terminals.

Unless you're going to place those marker heat-shrinks every foot or so I think it's a bad idea to reply on them exclusively. Sometimes you need to know which wire is which in the middle of a long run and if they're all green then which one is the one that you need? (I used green as an example because IH did their Scout II's this way. All green wire with numbers ink marked on them. Which comes off if you happen to use lacquer thinner to clean the loom..... )

Research it because I know that they're out there somewhere, there's a spiffy tool made that allows you to use a Dullie® (that's a Sharpie® after a couple uses) to put a stripe on any wire. I have one that a friend printed. The bonus is that you can use any color Dullie® that will contrast and show up on the base color.

Del City Wire was recently running a special on what looks like it might be a quality crimper that uses interchangeable dies, and that has a wide range of available dies.
Best Mechanic i know with 60+ years of electrical. He as went to the new crimp-op with built-on heat shrink.. add an extra heat shring tube over the top for connections in wet areas.. and this guy used to soldier every connection.. never used a scotchlock that i saw..
 

·
Super Moderator
Joined
·
8,862 Posts
Had my first run-in with one of those heat-to-solder-&-shrink connectors about 2 months ago. NOT recommended in any area that will see heat. Like under the hood. Nearly lost an engine to over-heating because one of those connectors in the electric fan circuit failed. The under-hood heat was enough to partly disconnect it. I'm not impressed, I'll keep using the crimp and heat to shrink Ancor terminals.

Unless you're going to place those marker heat-shrinks every foot or so I think it's a bad idea to reply on them exclusively. Sometimes you need to know which wire is which in the middle of a long run and if they're all green then which one is the one that you need? (I used green as an example because IH did their Scout II's this way. All green wire with numbers ink marked on them. Which comes off if you happen to use lacquer thinner to clean the loom..... )

Research it because I know that they're out there somewhere, there's a spiffy tool made that allows you to use a Dullie® (that's a Sharpie® after a couple uses) to put a stripe on any wire. I have one that a friend printed. The bonus is that you can use any color Dullie® that will contrast and show up on the base color.

Del City Wire was recently running a special on what looks like it might be a quality crimper that uses interchangeable dies, and that has a wide range of available dies.
Indeed. I used I think several hundred of those crimp-seal connectors too. They have glue lined heat-shrink which seals against the wire insulation and heals the cuts from the cirmper. Different colours for different wire sizes. Here's a pic of an audio loom I had to repair after some clown cut out a head-unit instead of unplugging it!

130770
 

·
Registered
Joined
·
1 Posts
When I bought my donor vehicle (72 Wagoneer) every bit of wire in the rig was removed. Along with the dash, interior, front clip, etc. The original 72 Jeep wiring system was based on all "in-line" fuses and very simple (and dangerous). The Full Size Jeep forum guys say it's not a matter of if, but when there's an electrical fire with the original wire harness.

On my first attempt at wiring this up I decided to buy a 91 Cherokee fuse box and use that package to adapt to the Wagoneer. Everything was going fine until I started breaking the plastic retainers that hold the wires into the back of the fuse box. Also, the little metal crimp connectors they used are not all the same. There's about 6-8 different ones, and the bus bars built into the fuse box are fixed and not all in a row. I had to buy a 2nd fuse box just for parts to try and replace all the broken clips. I've been driving it for a year with half the circuits complete and a rats nest of wires under the dash and in the engine compartment. I could finish the route I was heading, but it would just be more that I'd have to undo when I make it right. So I've been driving without dash lights or a dash switch for the heater fan. I have a household (inline fused) light switch under the dash so I have at least a defroster. It's super janky.

I was also doing the wiring one circuit at a time, so a lot of my runs were redundant, I wanted a dedicated ground for every circuit, a relay for anything over 5 amps and very limited power going through the firewall. Right now it's just signal wires and enough juice to power relay signals. I was using whatever wire I had from the two ebay Cherokee boxes so the wire colors don't make sense, and when they weren't long enough they'd change colors with a solder or crimp connector. I didn't have unified plan in mind

Adding to the complication of doing this at all is the fact that I have all these little converter boxes and adapters because this is a Frankenstein rig. Metric Isuzu motor, metric GM tranny, etc. etc. I have a dakota digital converter for the tachometer, another little brain box to convert my custom fuel tank level sender into something a 1972 dashboard can make sense of. I also want to use all the original dash switches and gauges work like it's original.

There is no kit for this. Not even close.

I know people do this all the time and say it's no big deal. I'm finding it overwhelming, and I'm writing several different documents:
A. Schematic (like relay diagrams, wire color, labeling method)
B. Diagram (where wires run)
C. Technical Data (spreadsheet - wire size, length, amp load, and fuse/relay size)
D. BOM (Bill of Materials, Parts list, vendors, costs.)
E. Mission Statement (Rules, safety, SOPs, tools to use, etc.)
F. Futures (AC, winch, compressor, Aux fuel pump, lights, inverter, etc)

That's enough of an intro. I'm going to document my progress here for your entertainment and open to suggestions as long as the suggestion is not "take it to a professional and pay them to do it right."
These pictures are embarrassing to post, but it's the truth and where I am now.

Cheers,
Kevin


If it were mine, I would spend the coin and go with a painless box and harness. These folks are easy to work with and extremely knowledgeable...
 

·
Registered
Joined
·
73 Posts
Locally Painless is known as "Painful". There are other options.
I have a vehicle specific kit from American Autowire that looks good. I've yet to install it though, so......
Ron Francis is the big name in hot rods.
Centec is another name that comes to mind. They used to use a PCB for their fuse panel, don't know if they still do or not.
I'm sure that there are more players in that field.

If determined to build from scratch I'll suggest that the wire be sourced from bestboatwire.com. That gets you decent wire with tin plated strands so corrosion is much less of an issue. You'll also want to get familiar with Del City wire, Waytek Wire, and powerwerx.com to name a few.
 

·
Registered
Joined
·
1,603 Posts
Yes I'm on a CLASSICBRONCOS.COM SIGHT . & Centec Ron FRANCIS are used there also But their both considered to be about $200.00 more than the PAINLESS.
FRANCIS & CENTEC are MUCH MORE PULG & PLAY . almost totally replacing the original..
But. I'm like ntspd .. I bought the American Auto wire & It was just perfect for my project & much cheaper .
I don't think anything in mine is stock except maybe the trail light connections .
 
1 - 19 of 19 Posts
Top