Thinking about building a wiring harness from scratch for a 40

[Volcano cruiser]

I was discussing my rebuild with a co-worker who is rebuilding his twin engine aircraft. We are actually doing many of the same things the same way but without consulting each other. When I mentioned to him that I was about to get the Painless kit he asked if I either had the original harness or a diagram of the OEM harness. Not the wiring diagram for the vehicle but the diagram of the harness. He was able to get one for the harness for his plane and is going to take the time to rebuild the harness, wire by wire from scratch using almost all new parts. While time consuming and alot of effort I love the idea. I have the time to kill while the body shop beats the dents into submission and hand sands everything down to the frame. To even consider this I can see two issues and I'm hoping that one of you guys can help me with. First, I need a diagram of the actual loom, i.e., the harness itself, not the wiring diagram for the truck. To do this right I think that I would do it like the old school factories did it. I get a diagram of the harness, blow it up to real size, tack it up on a plywood board and then build the loom wire by wire, connector by connector, branch by branch, physically on top of the blown up diagram. As each section is done, lay it over tacks on the board to hold it in place per the underlying diagram. Repeat process until each section is complete. At the end I should have the whole thing layed out on the tack board over top of the life size version of the diagram, just like the old school factory process. Bundle up each branch take it off the board and install per the vehicle wiring diagram in the FSM.
As such this is a non starter unless I can get a diagram of the OEM wiring harness. Additionally, I need a source for reasonably priced OEM striped wire. I just got the new catalog from Waytek and they say that they will do custom striped wires so I'll start there. I am interested in all suggestions for sourcing wire and the harness diagram. I had originally budgeted in the rebuild for the Painless setup. This project only makes economic sense if I can bring it in at or below that figure.
Under normal circumstances the fall back to no harness diagram would be to pull the existing wiring harness from the rig, tack it up on the plywood and re do it. Those of you who have followed my build thread have heard this rant, can't be done cause the the PO mercilessly fawked it up. Suffice it to say, there isn't a branch of the original harness that is intact as OEM, they have either been cut and spliced with whatever was lying around, wrong colors, different gauge wire or the wire just dead ends and never reaches from the switch to the item , e.g. horn, windshield wipers, oil temp gauge, etc. Honestly, I'm hoping that one of you is as big a pack rat as I am and somewhere along the way has snagged the harness diagram at a flea market and just has it stuffed away on a shelf gathering dust for awaiting its turn in line for some future project.

 

[3doghouse]

I'm rebuilding mine using correct wiring colors by scavenging harnesses from the junkyard.

It's very time consuming in the short run, but makes life easier in the long run.

 

[cruiserbrett]

first off, thats a big undertaking.

two points of concern.
1: there is not any factory wiring diagram that accurately depicts the location of components and connectors, so theres little chance to build it that way.

2. I looked into custom striping some rolls of wire and there is a minimum roll length, and so many colors and sizes its no where near cost effective, let alone will be be anywhere near painless kit price...

I think roll lenght min was 200 feet to stripe, and with a $.10/foot cost, and a $10 striping fee per roll you are looking at nearly $1000 for all the different size and color combos...

 

[cruiser7773]

I commend your desire to start fresh with the wiring and also to keep it original; Lord knows that the wiring is always a mess with these rigs when they have had 10 previous backyard-mechanic owners. I really can't imagine why you wouldn't what to go with a Painless harness. I actually do this kind of work on military aircraft, and replacing a harness is work enough without having to built it yourself. You will (or should be) doing what you mentioned with respect to mapping out the new harness with a Painless system without having to deal with the old fuse block. I can tell you from personal experience that the Painless harness works very well; I recently replaced all the factory wiring in my cruiser when I installed a Chevy vortec engine. The only part of the old harness I utilized was the 12" or so that run up the column to the ignition and turn signal switches.

 

[Volcano cruiser]

I'm rebuilding mine using correct wiring colors by scavenging harnesses from the junkyard.

It's very time consuming in the short run, but makes life easier in the long run.

3dogghouse,
so if I get this right, for example, as you need the white wire with the blue stripe you go through salvage harneses pull enough white wire with blue stripe and splice it together to make that section in the harness that you are building, yes? Wow!

first off, thats a big undertaking.

two points of concern.
1: there is not any factory wiring diagram that accurately depicts the location of components and connectors, so theres little chance to build it that way.

2. I looked into custom striping some rolls of wire and there is a minimum roll length, and so many colors and sizes its no where near cost effective, let alone will be be anywhere near painless kit price...

I think roll lenght min was 200 feet to stripe, and with a $.10/foot cost, and a $10 striping fee per roll you are looking at nearly $1000 for all the different size and color combos...

Cruiserbrett,
Thanks for the analysis. A couple of points. Logic would seem to dictate that the OEM harnesses got built. They are all the same (per production run and model year, etc.) Therefore SOMEWHERE there has to exist a diagram of how the harness itself is laid out. Are you saying that you just haven't seen one? Given the trouble I had trying to search one out I don't disbelieve you for a second. It just seems to defy logic and practice that the Japanese would engineer something as critical as an automotive wiring harness without a script for the joe six pack worker at the assembly plant. Second, do you remember where you priced the wire and custom striping at? I was about to call Waytek but if you got these figures from there recently then that saves me a step. If not I'll give them a ring to comparison shop. I will say that your minimum length figure is probably close, I saw lengths quoted in the catalog of 250 ft with no prices for striping.

I commend your desire to start fresh with the wiring and also to keep it original; Lord knows that the wiring is always a mess with these rigs when they have had 10 previous backyard-mechanic owners. I really can't imagine why you wouldn't what to go with a Painless harness. I actually do this kind of work on military aircraft, and replacing a harness is work enough without having to built it yourself. You will (or should be) doing what you mentioned with respect to mapping out the new harness with a Painless system without having to deal with the old fuse block. I can tell you from personal experience that the Painless harness works very well; I recently replaced all the factory wiring in my cruiser when I installed a Chevy vortec engine. The only part of the old harness I utilized was the 12" or so that run up the column to the ignition and turn signal switches.

cruiser7773,
Believe me I've got nothing against the Painless guys or their product. I'm really just exploring a project here. As you mentioned since I planned to stake out the painless kit on a tack board anyway how much more effort would it really be to crimp and solder (not saying which camp I'm in on that whole discussion) a few more terminals, connectors and fusible links if I can come up with an OEM replica result. Again, there are two keys to whether or not this idea is feasible, can I get my hands on a diagram of the harness and can it be done for anything close to the cost of the Painless kit. Without those two items being resolved then this gets filed in the drawer of projects to do when I got more time, energy and money than I know what to do with...

As you can tell I'm really hoping someone has a copy of the harness diagram. I might be able to skin the cost of wiring cat another way, maybe

 

[fjwagon]

The wiring diagram you are looking for does not exist, at least not to the general public. The diagram you are looking for should show you for example how long the ground wires should be, where it got spliced and different gauge wires used along the same circuit. It would not be hard to make your own harness using a fsm and your old harness. Even though the harness you have has been butchered, the main part of it is still there which can easily be copied. It would be wise to pull it and go from there or get another one from somewhere.

I just repaired a short and several "open" circuits in my 45. I also had a couple of bad terminals that were corroded. After figuring out where the problems were, how long they needed to be and the colors, I went the junkyard and pulled those wires I needed for the repairs. Lucky for me they ones I needed were already spliced by the manufacture so I did not need as much wire as I originally thought. About the only thing I needed that I did have or wanted to get at the junkyard was terminal lugs which I ended up getting at a compurter store.

 

[Coolerman]

I have some diagrams that may help. They do not contain dimensions but they do show how the harness is assembled.

Note these are for the earlier Cruisers not later models...

Here is a sample. There is a table that shows where each wire in a connector orginates , it's color and what connector it terminates at, and its function.

I can post all 15 pics here, or can email a zip file of them to anyone who wants it. File size would be 3.7 meg so make sure your email will handle a file that size.

I also have a spread sheet I did that shows all the OEM wire colors used on a Cruiser. There are 31 different colors BTW...

 

[Volcano cruiser]

I have some diagrams that may help. They do not contain dimensions but they do show how the harness is assembled.

Note these are for the earlier Cruisers not later models...

Here is a sample. There is a table that shows where each wire in a connector orginates , it's color and what connector it terminates at, and its function.

I can post all 15 pics here, or can email a zip file of them to anyone who wants it. File size would be 3.7 meg so make sure your email will handle a file that size.

I also have a spread sheet I did that shows all the OEM wire colors used on a Cruiser. There are 31 different colors BTW...

Coolerman,
This EXACTLY what I'm talking about!
Please zip file the lot to me via email. PM sent. Ok it seems that I might be over the first hurdle. The second one is starting to look pretty tall though, 31 different colors combos of wire, OUCH! Well let's see what we can do about that. Thanks.

 

[theo]

Maybe Painless will take pity and sell you some partial rolls of wire?

Should you build two harnesses to recoup some expense?

 

[theo]

. . . or can email a zip file of them to anyone who wants it.

I also have a spread sheet I did that shows all the OEM wire colors used on a Cruiser. There are 31 different colors BTW...

I'd like to ask for a copy of the diagrams and spreadsheet BEFORE you get so inundated with requests it drives you beserk.


And before you realize people would pay good money for something like that.

ted dot christian at umontana dot edu

 

[Coolerman]

These diagrams are Toyota diagrams I got from someone here on MUD. Remember, they are for the EARLY Cruisers and will NOT be accurate for later models!

 

[Coolerman]

On it's way Theo...

 

[3doghouse]

jabxyz - No, I pull the entire harness. The early mini trucks use almost the same harness, just different lenghts. Newer trucks have many of the same colors, plus some wires marked with dots to indicate exact circuits.

Coolerman - Please send them my way too!

Thanks!

 

[crushr]

Coolerman - would appreciate receiving the diagrams. Thanks for the generous offer.

Send to: Crushr at comcast dot net.

 

[Volcano cruiser]

Maybe Painless will take pity and sell you some partial rolls of wire?

Should you build two harnesses to recoup some expense?

Theo,
The thought had occurred to me. My bud suggested that I plan on making ten of these and t]recover costs that way, by selling nine of them. That sounds fine in theory but until I see the numbers on getting OEM striped wire I just won't know if this really makes economic sense.

These diagrams are Toyota diagrams I got from someone here on MUD. Remember, they are for the EARLY Cruisers and will NOT be accurate for later models!

Coolerman,
First, thanks again these look really great. Thanks for taking care of them for the rest of us until someone nutty enough to consider doing this came along. Point taken, I actually noticed that there are four harness diagrams, for various early models and early year 40's in the zip. I can see that another step to this will be seeing what later model parts or systems were added to the loom. At least with this I might have a start. Now I'll get onto the waytek guys and hear what they have to say. P.S. I agree, they have a great catalog. Thanks

jabxyz - No, I pull the entire harness. The early mini trucks use almost the same harness, just different lenghts. Newer trucks have many of the same colors, plus some wires marked with dots to indicate exact circuits.

Coolerman - Please send them my way too!

Thanks!

3doghouse,
Phew! The good news is it sounds like you have a great pick and pull nearby. I have no such luck.

 

[Soul_Man]

You don't mention what year your rig is (unless I missed it). Mine is a '78

The wire should be better quality than stock, I'd like to go up a size on each wire (not a big deal as stock worked fine) but want to get better quality insulation so it won't crack down the road.

I would be interested in:

1.) Buying a share of your left over wire so I can make my own harness also, or at least have it on hand for stock color replacing of my current bad sections. If your minium wire buy would be enough for, say 20 Cruisers, I'd be happy to buy 1/20th of it (and I'll bet you can find 18 others like me)

2.) Buying a complete harness if you do a good job

Remember, I asked first (I think, and I did read the other posts )

Alsof, anyone know if you can buy the stock connectors as I'm sure many of mine a crap/not reuseable

 

[Pin_Head]

It is almost always easier and cheaper to repair your "hacked" harness. It will take less work and understanding than making a new one.

If you don't want to go to the trouble of understanding the wiring enough to repair the one you have, then just get a good used harness. It is plug and play.

You don't need to use the original color wires. You can use other separate colors and just shrink wrap a one inch piece of the old insulation on the ends of the wire so it conforms to the color code of the wiring diagram.

 

[Nevinsj]

Coolerman,

I have a 74, if your wiring diagram covers that, please send me the zip file also.

Thanks!

Joe

 

[Volcano cruiser]

You don't mention what year your rig is (unless I missed it). Mine is a '78

The wire should be better quality than stock, I'd like to go up a size on each wire (not a big deal as stock worked fine) but want to get better quality insulation so it won't crack down the road.

I would be interested in:

1.) Buying a share of your left over wire so I can make my own harness also, or at least have it on hand for stock color replacing of my current bad sections. If your minium wire buy would be enough for, say 20 Cruisers, I'd be happy to buy 1/20th of it (and I'll bet you can find 18 others like me)

2.) Buying a complete harness if you do a good job

Remember, I asked first (I think, and I did read the other posts )

Alsof, anyone know if you can buy the stock connectors as I'm sure many of mine a ****/not reuseable

I have an 80. I still haven't reached out to Waytek though. I'll report back tomorrow after speaking to them. Thanks.

 

[Volcano cruiser]

It is almost always easier and cheaper to repair your "hacked" harness. It will take less work and understanding than making a new one.

If you don't want to go to the trouble of understanding the wiring enough to repair the one you have, then just get a good used harness. It is plug and play.

You don't need to use the original color wires. You can use other separate colors and just shrink wrap a one inch piece of the old insulation on the ends of the wire so it conforms to the color code of the wiring diagram.

Pinhead,
Thanks. The sad fact is that where I'm located most folks go to the dealership to get replacement parts and once discontinued they head over to a parts store. Salvage places are really a good bet only for large parts, e.g., doors, trunk lids, hoods, grills, engines, trannys, etc. For stuff like a harness they just keep pecking at it with temp repairs until it looks like mine does. As such picking up a used one here is out. Trust me if I thought that there was even a remote chance of that I'd have been all over it months ago.
As to going through the trouble to learn the wiring by repairing the old harness, maybe it's that I have a mental block, I just see red everytime I look under there, but I think that it would be just a hugely frustrating affair. I know that even after I pulled everything out I'd still be missing chunks of wiring as well as connectors. I can see myself burning hours tracing and testing each wire looking for breaks or bad connections.
The difference in building a new harness is that while I'd spend probably the same amount of time it would be without nearly the frustration and stress, To me it is just different building something v. cleaning up someone elses crap.
All this said I did get a chance to speak to the Painless folks today so my plan B is intact.
All of the above being said I think now, even if I do the Painless harness, I will carefully pull the OEM one, labelling stuff as I go, and lay it out on a tack board against the most complete Harness chart that I got from Coolerman and at least map out what circuits the present drawings are lacking from the later year OEM harnesess Thanks again,