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Technical Automotive wiring diagram software

Discussion in 'The Hokey Ass Message Board' started by kilohertz, Jan 25, 2022.

  1. kilohertz
    Joined: Oct 5, 2020
    Posts: 74

    kilohertz
    Member
    from Vernon, BC

    I am looking for ideas for an easier way than pencil, eraser and paper to design and document the complete new wiring harness(es) for my '49 Ford F-47. The truck is completely void of wire and I am beginning to do the layout. There are too many custom items I am adding so I don't want suggestions to use a prefabbed harness, I am building mine from scratch. I just need a software based program to allow me to get everything into a diagram that I can edit and print so I can do the design in the office, then build it in the shop.

    I have experience with Visio and if someone knows of an automotive template, that would be ideal. I would also consider any other freeware specific to the automotive wiring systems, I have used google and found a few but would like to hear from someone who has actually used it and some suggestions based on experience, and something that is currently available.

    Thanks for any tips or suggestions.

    Cheers
     
  2. I'll make a suggestion.... One place where guys make a mistake IMO (and the OEMs used to do it too) is trying to make a single diagram that has everything on it. Unless printed on a very large sheet (2 x 3 feet would be the smallest I'd use), the information density is such that the finished diagram can be very hard to read. And it's easy for mistakes to creep in; it's rare that I haven't found at least one mistake on the ones I've seen.

    Rather than go through all that, a better way IMO is to have multiple drawings covering each circuit individually. Most service manuals do have these separate diagrams, or at least some of them. Now you still want an 'overview' drawing, but rather than trying to cram everything onto it, make a vehicle 'map' showing major component and wire routing location. Simple one-line depictions of main wire routing and boxes for components. Number or letter the boxes for identification, and identify which circuits are routed where, again by simply numbering them. Provide a legend for identification. As a quick example, say the circuits going to the rear of the car would be brake/turn, taillights, fuel gauge, and fuel pump. That's five wires if doing a 'whole' diagram, but only one line with four identifying numbers for the four circuits as an overview. You no longer need a monster-sized sheet for clarity.

    You can then refer to the individual circuit diagram for the actual wiring, and here's where you include wire size, color-coding and any additional components like switches, junction points and relays. Include routing numbers on individual wires so you know where to look if troubleshooting.

    A number of years ago I bought a late-model and wanted to purchase the service manual for it. Turned out there were two and they weren't cheap. But a full wiring diagram was only $10, so I ordered it instead. Now this car had everything; EFI, ABS, power everything, cruise control, you name it. I got a manilla envelope in the mail with 40+ sheets in it, each unfolded into a 2 x 3 foot sheet with match lines on almost every side. No doubt useful if you really needed it, but tracing even one circuit would have been a major headache. I threw it all away....

    And I salute you for building from scratch; the aftermarket harness builders with their 'generic' designs don't address more elaborate harnesses well at all. You may find this of interest.... Wiring 101 | The H.A.M.B. (jalopyjournal.com)
     
    Last edited: Jan 25, 2022
  3. kilohertz
    Joined: Oct 5, 2020
    Posts: 74

    kilohertz
    Member
    from Vernon, BC

    Steve,
    Thank you so much for the detailed and insightful reply, I have learned in the last few years you are the wiring guru here, and yes, I have that Wiring101 open right now, I read all 19 pages last year when I was picking my interior fuse panel and am gong thru it again, great effort I am sure appreciated by many. I too am an electronics tech, over 45 years now playing with electricity, and am now looking forward to retiring in a few years and focus on building all of my automotive projects.

    That's a great idea, master drawing and sub-sections. I was actually thinking of breaking it down into "systems" rather than location, but as I am just starting will consider both. Perhaps engine bay, vehicle rear, interior, dash, gauges etc. and front end.

    [​IMG]


    I ended up with this for the interior fuse panel, still looking for under hood panel for relays and a few larger fuses.

    Do you use software to keep track of your wiring projects, if so, what? I think based on the amount I time I have spent looking for software, I will just stick with Visio and create the objects I want from scratch, most everything else on this truck is from scratch also. ;)

    Thanks for your help!

    Cheers
     
    TrailerTrashToo likes this.
  4. Well, I wish I could claim origination of the idea, but I learned this doing my craft as a construction electrician. The solid-state stuff was just starting to come into general usage, there was still lots of 'old style' hard-wired systems with relays and limit switches being installed not to mention all that existed. For anything other than the very simplest control circuits, there were always multiple drawings for clarity. The pisser was when the owner had lost the as-built drawings, that when you really earned your money.

    I'm no electronics expert by any means, I know just enough to find the bad component usually which I then hand to the tech and tell him to 'fix your stuff'... LOL...

    No computer software for me, I draw them by hand or copy out of a service manual. There is some software available that I had brief contact with before I retired, but it was expensive (several thousand $ for a license) and generally rather too specialized for our use here. If you come up with something easy to use, I'd love to hear about it.

    I'll be honest, I'm not a fan of aftermarket printed circuit boards outside of factory assemblies for several reasons. One, they generally don't handle high currents well. Two, due to their generally 'generic' nature they don't adapt well if you have anything oddball. The OEMs can use them as they'll build them to suit in whatever quantities they need and have economy of scale, not something the aftermarket does well IMO. And three, if they do fail they're usually not repairable and more expensive to replace compared to a 'standard' Buss fuse panel and/or relays. The only thing they do better is 'package' and given their expense they're not that much smaller. I think for the hobbyist, going 'old school' will not only be less expensive but easier to troubleshoot for the average guy. A four-circuit relay/overcurrent protection 'module' at $150 is hard to justify when four $10 relays and a $15 fuse panel will do the same thing.

    And I've said it before, but it bears repeating; the aftermarket over-uses relays, usually to mask deficiencies in their harness designs. Relays have their place, but a lot of common uses could be eliminated with better harness design.
     

  5. AccurateMike
    Joined: Sep 14, 2020
    Posts: 631

    AccurateMike
    Member

  6. kilohertz
    Joined: Oct 5, 2020
    Posts: 74

    kilohertz
    Member
    from Vernon, BC

    Hi Steve,
    Thanks again for the insights, appreciated.

    Not defending cct brds in general, but this particular one is very well made, and you have access to each and every pin on the fuses and relays, so it is VERY customizable, and I was able to obtain all the required connectors and pins for it very cheaply. The panel itself was only $100, much cheaper than the "mainstream" aftermarket stuff. The relay sockets can be configured for flashers or relays, 2 different types and there are separate battery and ignition inputs on it, 90 and 70A respectively. It came from Digikey, readily available.

    I started drawing the overview diagram in Visio and it looks good, I am going to try to do maybe the lighting cct to start with and see how it looks, then carry on with the rest of the vehicle. I think I will stay with my "drawing by system" so that all lighting is on one page etc.

    Cheers
     

    Attached Files:

  7. kilohertz
    Joined: Oct 5, 2020
    Posts: 74

    kilohertz
    Member
    from Vernon, BC

  8. squirrel
    Joined: Sep 23, 2004
    Posts: 55,932

    squirrel
    Member

    Might also consider wiring lists. The last car I built had several screw terminal blocks (barrier strips), and each one has a list of what wires are connected to which terminals, with color and the destination of the wire and circuit description. here's an example. I needs to be entered into a spreadsheet, eh? but that's not really how stuff works on the HAMB, we're more pencil and paper.

    I also have some schematics from another one, sort of one page for the stuff up front, another for the dashboard area, and one for the back. Crayons let you know what color the wires are. Again, this is the HAMB, old technology is fine here.

    The barrier terminal strips really help with troubleshooting and modifications, and also provide an old time look that you just can't get with modern plastic hermetically sealed connectors.

    wiring3.jpg wires 1 dash.jpg
     
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  9. Frank Carey
    Joined: Oct 15, 2009
    Posts: 574

    Frank Carey
    Member

    I always wait for Crazy Steve to post before saying anything electrical. He is wise. Now that he has, here's my $.02

    1. Paper and pencil
    2. Separate pages per function (per Steve)
    (E.g. starting and charging, head and tail lights, etc.)
    3. I show schematic representation of relays and switches to help me do trouble shooting. (Showing a relay as a box with five wires to it doesn't help)
    4. I include notes to help understand for when I'm trouble shooting or making changes (e.g. why two 12V supplies to headlight switch, - one for headlights and one for everything else. Why there are two 12V supplies to wipers (one from on/off and one always on to keep wipers running until parked after they are turned off. It turns itself off when parked)
    6. I use connectors or terminal blocks when wiring removable items like headlights
    7. I plan the paths for routing wires and run wires individually rather than fabricate a harness on the bench and then (try) to install it. I lace harness when all wires have been run.

    Hope this helps

    Frank
     
    loudbang likes this.
  10. LAROKE
    Joined: Sep 5, 2007
    Posts: 2,079

    LAROKE
    Member

    I admit it, 'tricity is a black voodoo magic to me. When I re-wired my '55 Chevy pickup, I got a one page "wiring diagram" from the vendor that I couldn't make much sense of. I spent some time with a meter doing a continuity check on each wire in the harness and recording my findings on an AutoCAD drawing (free autocad substitutes exist out there). I used images of lights and gauges rather than symbols in light of my novice knowledge. The great thing about CAD software is the use of layers and I put different circuits on separate layers which could be viewed and printed by turning the other layers off in the software. When it came time to wire rewire the truck, I did it in a day and a half and when I turned it on the first time, no smoke escaped. Here is a link to my diagram in PDF file format.

    http://www.laroke.com/larryk4674/2007/bbwiring1.PDF
     
  11. Paul
    Joined: Aug 29, 2002
    Posts: 16,380

    Paul
    Editor

    I use AutoCAD too.
    No electrical specific templates.
    Once you have one diagram drawn up it becomes a template and can be modified to fit the next job.
     
    LAROKE likes this.
  12. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,214

    ekimneirbo

    Even though you are electrically proficient, its easy to overlook some issue or problem that you may create when building from scratch. For simply doing colored lines and boxes with labels in them, I just use "Microsoft Paint" to do simple diagrams. It was on my computer and therefore I used it.
    Rather than creating something totally from scratch, my suggestion is to copy a wiring diagram from one of the companies that make universal harnesses and sell them. Save the copy to a Paint file and then you can erase what you don't want and add what you do want. I can understand wanting to create your own harness from scratch, but trying to also design an unproven complete harness with absolutely no flaws in it is a pretty difficult job.

    Here is a simple Paint diagram I made for a guy who was working on a fuel system. You can see what its like.
    x1 001 xx.jpg

    Also I would suggest buying a copy of this book which has loooooottttsss of little tips on which components differ from brand to brand.
     

    Attached Files:

    Last edited: Jan 27, 2022
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  13. Paul
    Joined: Aug 29, 2002
    Posts: 16,380

    Paul
    Editor

    One of my go to sources for basic wiring is this old book by MOTOR.
    No new fangled gizmos here, just good old proven basics in an easy to understand format.
    Plenty of illustrations to help a novice like me too.

    PXL_20220127_230215860~2.jpg PXL_20220127_230309560~2.jpg

    from that illustration I drew up a basic diagram for a project I was working on

    basic wiring diagram 4.0.jpg

    and modified that slightly to work on another

    23 rdstr wires.jpg
     
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