68 wagon fuel sender wiring path

Discussion in 'Drag'n Wagons' started by johnnyboy, Aug 5, 2018.

  1. johnnyboy

    johnnyboy Member

    Hi all,

    I'm trying to track down an apparent short in the wiring from the fuel gauge to the tank sender in a '68 Special Deluxe wagon.

    Does anyone know the specific physical path of the wiring harness that includes the sender wire, and the locations of the applicable harness connectors, especially the point at which the wire from the sender enters the cabin? I'm trying to avoid disturbing more carpet or headliner than is necessary to locate and test the wiring and fuel gauge. Any additional tips or suggestions would also be greatly appreciated.

  2. TrunkMonkey

    TrunkMonkey Well-Known Member

    The rear, from the sender on the front of the tank. boot, small tan wire, runs forward and over the axle on the drivers side and passes through a body plug to the intermediate ribbon harness connector.
    That can be accessed by pulling the rear seat bottom (not 100% on how that works with a wagon) But the connecter and ribbon ar about where the seat back and bottom meet.

    Then one line on the ribbon harness to the front, and from that ribbon harness connector tan wire to the post on the fuel gage.

    The ribbon cables are pretty stout, and other than a bit of oxidation or corrosion at the ends where the connectors are, you can Ohm that and make sure you have continuity, then focus on the sender or gauge and the tan wire for any breaks, and not have to pull carpet.
    johnnyboy likes this.
  3. BuickV8Mike

    BuickV8Mike SD Buick Fan

    I think the ground is a BLK ring type. I used a binder clip to attach it to the edge of the gas tank, no issue so far.
    johnnyboy likes this.
  4. johnnyboy

    johnnyboy Member

    Awesome. Thanks guys.
  5. johnnyboy

    johnnyboy Member

    Just to close the loop on this subject:
    The tan wire from the fuel tank sender unit in my '68 Special Deluxe Wagon comes down from the top of the tank and meets a simple bullet-type connector near the bottom rear corner of the tank, where the wire then joins a harness.
    Disconnecting this bullet and connecting a simple circuit tester light to the end of the wire coming from the harness produced a light, and connecting a simple jumper from that same wire to ground caused the fuel gauge to go from super full to flat empty. These tests indicate that both the gauge and wiring to the gauge are good, and that the problem lies with the sender unit or the ground wire from the sender unit. The ground wire can barely be seen from below the car and ends with a ring terminal screwed to the back of the inner wheel well. Unfortunately, there is very little space between the tank and the wheel well so this ground wire can't be reached without dropping the tank, and thus can't be tested without doing so.
    I'm not inclined to go through the hassle of dropping the tank unless I can locate a new sender unit (specifically for a '68 wagon) just in case, and I would actually prefer to just go ahead and replace the whole tank while I'm at it.
    So far, no luck locating a new sender or tank for this wagon, so I'll just live with it for now. If nothing turns up I guess I'll eventually drop the tank and, if the sender is the culprit, see if it can be repaired or if a sender for a sedan or something can be made to fit.
    Anyone have any experience going that route with a wagon?
  6. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Find a sender and drop an empty tank. Its not so big of a job and can easily be done by yourself.
  7. BuickV8Mike

    BuickV8Mike SD Buick Fan

    I speaking about in general, as I don't have wagon experience.
  8. flynbuick

    flynbuick Super Moderator Staff Member

    Your sender or another core can be rebuilt by Tri-Starr Radiator which I recall is in New York.
  9. bostoncat68

    bostoncat68 Platinum Level Contributor

    I suspect finding a new or even good used tank will be a hassle but you can easily find someone to refurb or take that on yourself. For my cat the worst bit was getting the bolts loose from the straps.... I treated multiple times with pb blaster weeks ahead -- really helped. Build sheet was still on top of tank :_)
  10. johnnyboy

    johnnyboy Member

    Thanks for the suggestions, guys. I've dropped tanks before and although it's no fun, it's generally not too bad. However, I've never dropped a tank from a wagon, which in this case is situated behind the left quarter panel and configured lengthwise rather than across the width of the car like most sedans, coupes, etc. The configuration looks very tight but otherwise pretty straightforward. But we all know how that can go.... I really would like to replace the tank and the sender if I do go through the trouble. The tank's filler pipe lip is bent up where somebody apparently pried off a locking gas cap at some point, so the cap doesn't seal very good now. And it's a 50-year-old tank anyway.
  11. johnnyboy

    johnnyboy Member

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