TH400 kickdown wire

Discussion in 'The "Juice Box"' started by matt68gs400, May 23, 2019.

  1. matt68gs400

    matt68gs400 Well-Known Member

    95A81782-997F-47ED-9573-7AD025870ADB.jpeg My transmission downshift wire is missing. I knew about this a while back and then it went on my list of things to do.

    Anyways, I see that a 16 gauge yellow wire feeds the gas pedal switch, from the radio. Then it leaves as a black/white wire back through the firewall and then to the transmission.

    Is this black/white wire also 16 gauge? I imagine it would be the same.

    I want to keep the wires the same color as it’s much easier to follow wiring diagrams that way. Somebody did some “rewiring” under my dash a while back and it looked like a Christmas tree assorted light set..... fun following that and getting it colored correctly.

  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    It comes off the firewall connector, so you can probably run it the same way you would for replacing the resistance wire for the ignition. If you know the right position, you can clip it into the connector with the packard 56 terminal.

    Barb type connector.jpg
    mk23mod0 likes this.
  3. matt68gs400

    matt68gs400 Well-Known Member

    Ah thanks! This is good news. I have some of those. My wiring diagram shows the correct position. Should be a fairly quick fix....

    I was thinking I’d go 16 gauge, same as the wire inside the car. It’s a short run and I think it’s low amperage?
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yeah, that should be fine, it's just a small solenoid you are triggering, not much current at all.
    matt68gs400 likes this.

    BRUCE ROE Well-Known Member

    Your 16 gauge wire should have a 12V source fuse in the 5A to 10A range. Bruce Roe
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    If he hooks it up like stock, that would be the radio fuse.
    matt68gs400 likes this.
  7. matt68gs400

    matt68gs400 Well-Known Member

    Ok, I got the wire hooked up. It works intermittently. I put a voltmeter on the terminal and pushed the gas pedal by hand. It would read 12 volts at times. Same with at the terminal switch by the pedal. Looks like a faulty foot switch. The switch looks like it’s the original 50 year old switch.
  8. matt68gs400

    matt68gs400 Well-Known Member

    Yep, it’s still stock. That’s where it still is.

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