Playing with the wires like a dingus?!

Discussion in 'The Bench' started by Brendan1972GSX455, Mar 12, 2018.

  1. Hey all,

    I'm currently working on rebuilding the wiring to my Skylark, and I have a small hiccup in my plans. Since my original wiring diagram was destroyed by mother nature, I'm left scratching my head at a plug-in spot on the back of the fusebox. If my guess was correct, this is where the battery runs into the box, which just means I need to get the battery portion of the harness to plug in.

    (Picture attached for clarity, btw.)

    Am I being dumb, or is there more/something else to this? Any help will be reciprocated with beer and/or words of wisdom.


    Attached Files:

  2. TrunkMonkey

    TrunkMonkey Well-Known Member

    The firewall/bulkhead block has a "interior side" and an "engine side". The engine and or front harness(es) have the multiple wires terminated with "Pack TwinLock" terminals, they are identical termination and interlock with each other. (like two people shaking hands).

    You need the correct engine side connector and the terminals.

    If you are comfortable doing your own work, you can get the terminals and appropriate crimps and dies to do them.

    Is all your wiring on the engine side of the firewall in good shape and long enough to terminate?

    I am sure you can find a connector or a"parts harness" for your car and re-use the connector.
  3. I'm familiar with that hardware. I just need to know where the wires RUN to.

    Is that open plug on the engine side all recieving battery power?

    And I got a new harness from OPGI, so the engine harness is in brand new condition.
  4. TrunkMonkey

    TrunkMonkey Well-Known Member

    I misunderstood your OP.

    If you have the OPGI harness, than it should have the plug that mates to the firewall connector in your picture.
    And I am certain is has the "battery" feed on a 10 AWG in that connector and the "ringed" terminal that connects to a Positive lug that is common to the starter and battery. (But I am not familiar with the 1972 for the battery common connections)

    My apologies if I wasted your time.

  5. Yeah, the picturw is whats currently in my possession. The OPGI portion of the harness only connects to 1/2 the engine side. (I'm sure I can find the parts to make the other half.)

    If anyone wouldnt mind supplying a pic or two of their box plugs, thatd also help.
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Wouldn't one half be the engine harness and the other half be the headlight/parking light harness?
  7. Thats what i'm trying to figure out
  8. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    the side your missing is for the lights. the car should run with out that half just fine
  9. TrunkMonkey

    TrunkMonkey Well-Known Member

    Yes. The front harness is lights, horn, turn signals.
  10. Okay, fantastic. Getting the gears turning is my main objective right now. Who needs to see at night anyways, am I right?

  11. Okay, so now I'm doing more looking around in my engine bay. All these diagrams call for a starter coil, but I cant seem to locate one for some reason.

    The engine harness shares common connections with the battery, but any sort of physical connection TO the battery wasnt included.

    This complicates things, because my distributor takes connections from a coil. (Pos,neg,ground).

    Should I just go buy one and build it into the harness according to the schematic?
  12. buick64203

    buick64203 Just plum crazy Staff Member

    What you took a picture of is called the bulkhead connector. On the engine side, there is a 1/4-20 bolt right in the center that holds both harnesses in. One side is the forward lamp harness and to the left, the engine harness plugs in. The forward lamp harness and the engine harness slide together and then both of them plug into the bulkhead connector. Once they're plugged in, you tighten up the bolt which take a 3/8" socket.

    Take a pic of the harness you have and we can tell you what goes where. No problem
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    All the battery power comes from the + battery cable, it connects to the big lug on the starter solenoid. Not sure why you are referring to a starter coil, I'm thinking that is the starter solenoid which is piggyback on the actual starter. The starter solenoid has one big stud connection, and 2 smaller ones. The + battery cable goes from the battery to the big stud on the solenoid. On that same big stud, there are the 2 main power feeds (Black and Brown wires) for the car and headlights. Those 2 power feeds are 10 and 12 gauge, the former for the entire car except for the headlights, and the latter for the headlights. Both are protected by fusible links right at the starter solenoid. The coil is fed through the engine harness. Power is supplied by the larger main feed wire and runs through the bulkhead connector, ignition switch, and neutral safety switch. You shouldn't need to make any other connections to the coil, they are part of the engine harness. The other smaller connections at the starter solenoid are the solenoid activation wire (S purple), and the coil resistance wire bypass (R yellow). Look at the diagram below.


    The Yellow R wire (resistance wire bypass) is described in this linked thread,
    Last edited: Mar 18, 2018

Share This Page