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Thread: Ham's 48: Make it go "HOOT"

  1. #1
    Super Moderator LarrBeard's Avatar
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    Ham's 48: Make it go "HOOT"

    I firmly believe that no matter how good an old Jeep looks to viewers, the owner always knows that there is just “one more” thing that needs to be improved on. Ham’s ’48 is certainly in that category – maybe more than “one more” thing on the list, but still – there is a list.

    One of the mysteries that had lurked in the beast since the first days it awoke from its 35-year hibernation was; “Why won’t the horn blow today?” It had a new wiring harness, the horn had been rebuilt but one day it would blow, the next day it wouldn’t and some days it wouldn’t stop blowing until it was good and ready.

    SO, early this month I decided that it was time to get to the bottom of the mystery. I grabbed a handful of clip leads and started testing things. The connection from the battery to the horn was good – it always had power to the hot side, one wire was eliminated as being the problem. If I grounded the other horn terminal with a clip lead, it hooted every time, so it wasn’t the horn. The wire from that terminal of the horn wanders through the harness and breaks out just below the steering column. There is a Bakelite plastic connector there, so I checked it out. The connector and the wire back up through the harness to the horn was good – another wire segment checked OK.

    All that was left was the wire that runs up the steering column to the terminal under the horn button. I connected my meter to the wire coming out of the bottom of the steering column and checked for continuity to the horn button contact. It was good too – but then it wasn’t.

    If I wiggled the contact that was crimped to the wire at the horn button end, it was intermittent! Finally – something that made sense. I put on my set of magnifiers and looked very closely at the contact that has been crimped to the horn wire. The horn wire has a color-coded outer cover and a rubber inner layer of insulation. The contact has two sets of crimp ears; one to be crimped to the two layers of insulation to give mechanical support and one set to be crimped to the copper inner conductor for the electrical connection. When the harness was made, the wire had been improperly stripped. The ears that were supposed to crimp the insulation did indeed catch both layers, but the inner rubber insulation had been improperly cut. It stuck way out beyond the outer layer of insulation. The second set of crimp ears were crimped to the rubber inner insulation instead of the copper center conductor. The only contact with the conductor was when the wire happened to flop around in the barrel of the contact. (The attached picture may make more sense...)

    I talked to Mike at KWAS and he sent me a horn button kit for the little Jeeps. It was close, but the center contact for the little Jeeps is a flat contact; the truck needs a more rounded contact, so that didn’t work out.

    SO, I put my magnifiers on again and started trying to peel the old contact off the wire. I broke some of the crimp fingers, but there were enough left to squeeze the contact back on and I was able to make a pretty fair solder joint to get a good electrical connection. The horn hoots reliably now. I still need the conical spring to make it a little closer to original, but it works better now than it has worked since 1962 when the whole horn guts came out of the wheel and my Dad just rubbed the wire on the nut to blow it.

    Now, on the next project on the punch list – that leaky differential vent!
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    Last edited by LarrBeard; 03-30-2021 at 08:59 AM. Reason: Added Another Picture

  2. #2
    Super Moderator gmwillys's Avatar
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    Great job Chief. Intermittent electrical issues can be tough to track down, unless you follow the every circuits and wiggle each wire.

  3. #3
    Senior Member 5JeepsAz's Avatar
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    Might have the same problem. Great info!

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    Super Moderator LarrBeard's Avatar
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    Intermittent electrical issues

    Quote Originally Posted by gmwillys View Post
    Great job Chief. Intermittent electrical issues can be tough to track down, unless you follow the every circuits and wiggle each wire.

    I know you've been there and chased that ... trying to pull crimped contacts out of a 57-pin MS Connector to get to the one wire you need to look at. Our Engineering Assembly Shop cable ladies always did a great job, but when we had to outsource for production cables, we almost always had strip/crimp/tool issues with the new lowest price vendor.

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    Super Moderator bmorgil's Avatar
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    Quote Originally Posted by LarrBeard View Post
    Now, on the next project on the punch list – that leaky differential vent!
    That diff leak is, baffling.....

  6. #6
    Super Moderator gmwillys's Avatar
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    A good portion of our harnesses are sub contracted out to the lowest bidder outfit out of Mexico. We have lots of issues with bad/wrong diodes, broken wires, pins that won't lock in place, improper crimp, or just plain pinned incorrectly. What is real entertaining is when you have an issue, and you pin out the harness and everything checks out with the DVOM, and everything works when the harness is slaved in just to find out that when the harness is installed and tied into place, a pin pulls back when ran according to the print. What makes the job fun is when the harness runs from the nose of the vehicle, then all the way to the rear wall, especially if there was a dead short, and all of the magic smoke is released, and melts the corresponding plastic air lines that travel down the same paths that the harness runs.

  7. #7
    Super Moderator LarrBeard's Avatar
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    Yep, same thing in airplanes...

    One of my favorites is the one undersized pin that won't lock into the backshell and then backs out when you engage the connector

  8. #8
    Super Moderator bmorgil's Avatar
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    I always felt those "pin" connectors were as cheesy as they get, yet we use them in the most sophisticated and cannot fail circumstances. I am so used to the way my dad hooked up his HAM gear and worked on his electrical hobbies in the 60's and 70's. He spent a great deal of time teaching me how important a good soldered connection was. The danger of the cold solder joint. Good connections were always very important. You think we could come up with something better.

  9. #9
    Super Moderator gmwillys's Avatar
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    The commo cables are the worst. Tiny pins that bend over when you look at them sideways. Testing commo starts with turning the system on, then go around to see why each crew station doesn't want to work.

  10. #10
    Senior Member TJones's Avatar
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    Here you go Larry it’s close to you

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