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Gas gauge no worky

Discussion in 'The Garage' started by 73K5Kid, Oct 20, 2004.

  1. 73K5Kid

    73K5Kid 1/2 ton status

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    Can someone tell me how to tell if my gas gauge is bad or if my sending unit is bad. Gauge is reading at empty even with a full tank of gas. And if it is the sending unit is it a pain in the A$$ to change. Thanks
     
  2. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    You need to find the wire coming from the sending unit and put an OHM meter across it and the frame.EDIT(you may want to disconnect it from the gauge. not sure if the ohm meter would find a ground through the gauge) Do that and then drive out a noticeable amount of gas and then do it again. If your reading changes your sending unit is good.

    The sending unit isn't to bad to change its getting the tank out that sucks.
     
  3. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    If its reading empty all the time, the circuit is either shorted to ground, or open all the time. can't remember which is which..

    How about turn the ignition key to the run position so the dash gauges will come on..
    Now go disconnect the brown wire that goes to your gas gauge sending unit.
    Look at your gauge and the needle should go all the way one way. (can't remember if its all the way full or empty.)
    Now Ground that connector against the frame.. and the gauge should sweep all the way to the other direction. (from all the way full to all the way empty, or vice versa.)

    This simple test will tell you if your Gauge, and the wiring all the way out to that connector is good or not.
    If the gauge goes from empty to full when you ground the connector, that tells you that your gauge and wiring is fine, and your sending unit is bad.
    If you disconnect the wire and ground it and the gauge isn't doing anything, than something is bad before the sending unit- like the fuel gauge or the wire going out to the sending unit.

    good luck. /forums/images/graemlins/waytogo.gif
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    With key on, put the pink wire to ground. (frame, whatever, just make sure its a GOOD ground.) Apparently other color wires were used. On non-EFI applications, black is the ground, the other is the gauge wire.

    With key on, pink wire grounded, the gauge should peg out.

    If it stays on empty, you might be having a ground issue, which is fairly common. Find the black wire coming off the top of the tank, pull it, and clean where it contacts the frame or crossmember, then reinstall.

    Senders are fairly easy to "fix" (although I can't get mine to 100% factory specs) I just wrote about "fixing" them.

    If the gauge isn't moving at all, I'd suspect it's a wiring or sender issue.
     
  5. 73K5Kid

    73K5Kid 1/2 ton status

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    Thanks everyone
     

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