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Sending Unit wiring

Discussion in 'The Garage' started by danny7139, Jan 8, 2006.

  1. danny7139

    danny7139 1/2 ton status

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    I have a 88 blazer here, fuel gauge never worked for me and now Im redoing the fuel system. The old sending unit had 4 wires coming out the top and 2 of them (purple and grey) going to a connecter and 2 others (black and black with white strip) spliced together and grounded to the frame. Well I got the new sending unit and its all the same expect the connect is 3 wires and 1 ground for the frame. The wires are the same colors purple black & white strip and grey going to the connector and black wire for the ground. Now what do I do with the new connector if it has a 3 wire connector?

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  2. danny7139

    danny7139 1/2 ton status

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    someones gotta know please
     
  3. sweetk30

    sweetk30 professional hooker Premium Member

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    is the sender in or out of tank? if out just trace the wires to each part and thats what thay do. most of them 99% time use black or black with stripe for grounds. gray is power to pump and purple is sender on gm if i recall correctly.
     
  4. danny7139

    danny7139 1/2 ton status

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    Well my old sending unit is out and its the same as the new model. I know the black wire is a ground but the black white striped on the wiring harness is what is confusing to me. Maybe another ground that goes up front?
     
  5. sweetk30

    sweetk30 professional hooker Premium Member

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    each ground is for the seprate part. pump and sender. but i could be wrong
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    First off it looks like somebody already screwed your fuel pump wiring up. The connector is only a 2 prong (power to fuel pump and gauge sender wire) and the third wire off the sender is the ground. Your connector in the top pic is what mine look like. But that heat shrink tubing and electrical tap(?) on that lower mass of wires does not scream "GM" :)

    I can't help you, I haven't seen a sender that has the wiring connector like you've got, and I have 3 different ones from exact unknown years, but all '87-91 TBI. And all are two prong plugs.

    One wire connector on '73-86 senders (fuel gauge) plus a separate ground, add one wire for the electric fuel pump '87-91.
     
  7. danny7139

    danny7139 1/2 ton status

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    well both of the sending units have 4 wires same color coming out of the sending unit, so I know there the same but what I do get is the 3 prong connector and a ground instead of a 2 prong and the black w/ strip and black wires as grounds on the frame.
     

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