Wiring harness to fuel pump

Discussion in 'GM Electrical Tech' started by spaceball04, Jun 16, 2010.

  1. spaceball04

    spaceball04 New Member

    I need help from the community again.
    I have a 1997 Express 2500 van and I'm troubleshooting some fuel pump issues.
    I have replaced the pump that was intermittent in it's operation and still have no fuel pumping or hear the sound of the pump working. I have replaced the fuel pressure relay.
    Is there another fuse in the box under the hood?
    My diagram on the box lid is messed up and I can't read it.
    I noticed a section of the harness had been pinched against the frame and so I want to check those wires for the proper voltage.
    I have 4 wires in the harness.
    Black (largest wire gauge of the four)
    Tan or Yellow (I can't tell exactly)
    Also, when I put in the previous pump about 2 years ago, immediately the fuel gauge would go back and forth when using the turn signal.
    With this new pump the gauge fluctuates the same way.
    Any help is appreciated!
  2. dualdj1

    dualdj1 Rockstar 100 Posts

    It sounds almost like a ground problem to me, with the turn signal/gauge issue.

    Get a manual for it, and check to see which wires are which. Check the ground (probably the straight black) vs the chassis with a multimeter and make sure it's not open (open = not connected to ground). Then check the feed wire with the key on (or while having someone turn the key on for you, as they'll cycle up and shutoff when pressure is achieved). If you have no power on the feed wire, then check at the relay and make sure it's outputting power when key is turned on.

    With electrical you just have to kinda work through it till you find the culprit. Multimeter and test light are your best friends :)
  3. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Did you replace the pump only, or the entire sending unit?

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