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What the heck did I blow?

Discussion in 'GM Electrical Tech' started by rellis, Oct 2, 2012.

  1. rellis

    rellis New Member

    I have a 1997 GNC Suburban with the 5.7l.
    THe power window lock was not working, so I did a dumb thing and jumped the hot lead to one of the other three leads and PRESTO, the other three windows would operate on their own once again. I didn't start the truck then, but everything worked normally with the key in the accessory position.

    THEN....

    THe wife tried starting the truck and got nothing. By nothing I mean no dash lights, no cranking, absolutely nothing. As if the battery was removed. I checked the battery and it still has proper voltage.
    So I inspected all of the fuses in the underhood box on the driver's side, as well as the fuses in the panel on the driver's end of the dash. All look good.
    Wondering if I had blown the starter relay, I swapped in the identical relay from the A/C. Still nothing.

    What else can I check?
    Could I have fried the ECM somehow?

    If someone has the wiring schematics, I jumped the yellow wire (terminal 1 of 4) to the dark blue wire (3 of 4).
    And remember, the damage was done not when I jumped the terminals, but when I tried to start it with those terminals connected.

    Please help!
  2. Pikey

    Pikey Moderator Staff Member 2 Years ROTM Winner 1000 Posts

    did you run the battery down while you were testing the windows? Here is a screen shot of the schematic

    Attached Files:

  3. rellis

    rellis New Member

    Thanks for the reply Pikey.
    The battery still has a full charge.
    Looking at the schematic, I only see two wires for the lockout switch, yellow (hot) and dk blue, which are the two I connected. I may not make any difference to the solution, but in reality there is also a black (I assume ground) wire and a dk brown wire that go to that switch.

    I strongly suspect I blew, or short circuited something, even though your schematic makes it look as though my solution should have worked.

    Other than the two fuse areas I checked, do you know what else might have tripped that would make the vehicle act as if there is no battery at all?

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