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  1. #1

    Default Where Can I Find Reliable Electrical Schematics?

    I am fed up with these horrid inaccurate wiring diagrams, Hanes and Chilton manuals are my primary complaint now.

    SO! Where do I find an accurate electrical schematic for a '90 GMC Sierra 2WD 1/2 ton with a V6 and manual tranny and a '91 with a 5.7L TBI (K) and a THM700 tranny.

    There seems to be part of the electrical harnesses from both in my truck. The engine, tranny, & electrical harness seem to come from the '91, except the part of the harness in the engine compartment that come out of the firewall on the drivers side and feeds some of the engine, the grill area and rear of the truck, that seems to be original.

    Both halves of the coupling at the firewall are the same and connect but the wires are not in the same locations and thus not connecting to the proper things on the other side of the firewall.
    Sincerely Jon

  2. #2
    TRPLXL2's Avatar
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    Jan 2009
    Norwalk, Ohio
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    All data is excellent for wiring diagrams, it's an online thing you can print off of. It's not free, I think it's like $14.95 per vehicle for a one year subscription. Paper wise helms manuals are the best, I have them for all my vehicles. $200+ per vehicle, but I can't live without them.

  3. #3


    Public libraries often have an automotive reference section with various professional and DIY manuals. Larger libraries naturally have a more complete selection -- and may even have the wiring and vacuum diagram volume. Some libraries even have subscriptions to some of the online references that may allow you access for free.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

  4. #4


    WOW! I cannot believe that I forgot that one.

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