Accidentally hooked the Engine Harness to the Dash Harness incorrectly in one spot and fried a wire. My car is a 2/'70 240z. The wire friend comes from the Engine Harness, though the firewall, and has a four-wire connector holding a Red, Blue, Blue/White, and Blue/Yellow. The Red wire is the one that is fried. Can anyone identify where this Red wire leads to? Was unable to discern from the FSM. Car cranks now but won't turn over. I'm wondering if this wire leads to the ignition coil.

Thanks, I need to re-wire this single wire and don't know where it leads.

Sorry - the photos:

#1) The wire inside the firewall that was fried.

#2) Wire that appears to have fried up by the Drivers Side Horn

#3) Wire that appears to have fried up by the Passener's Side Horn

My suggestion is to get out your Ohm meter and start checking continuity to see where the wires go. If you think it goes to the coil, check that first.

(There are a lot of red wires in the wiring harness...)

I fear the problem is worse than you think. There are no red wires in the ignition circuit. The red wires by the horns appear to be for the optional factory fog lights, which were never used in US cars. But since something is connected to the left red wire, I can't say that for certain. But if the left one is the fog light wire, the wire that is plugged into it may be the root cause of the meltdown.

But since the car won't start now, I'm guessing that the red wire got hot enough inside the harness to melt other wires inside the bundle where you can't see them. You may need to unwrap the harness to find and repair the damage. If the damage is extensive, it may make more sense to replace the engine compartment harness.

Edited July 16, 201113 yr by Arne

(slaps face with palm)...

Just when you think you're almost done with a project, one moment of carelessness ruins the whole thing. Taking apart the engine harness is the next step, though I was hoping someone might identify where that 4-wire set on the Engine Wiring harness leads to.

I really need to add a facepalm smilie to this forum. They are so useful...

Those colors must be the colors on the dash harness side of the connector?

Bill, be sure to check the fusible link between the starter and the engine wiring harness. I think Arne is on to something as far as overloading when you crossed the streams. You created a dead short that wasn't protected by a fuse. Therefore, there's a good chance the fusible link took a good shot of current, too.

Edit: Oh, and there is always the chance that you fried the ammeter in your dash, too. That could prevent starting. I've seen that before.

Edited July 17, 201113 yr by SteveJ

I don't think the fusible link is burnt. If that were the case, I don't think the ignition switch would be powered, so turning the key would not allow it to crank.

I don't think the fusible link is burnt. If that were the case, I don't think the ignition switch would be powered, so turning the key would not allow it to crank.

D'oh! I missed that. I'm trying to remember if the fried ammeter allowed the starter to spin. Unfortunately I have to finish getting ready for my trip to the convention, so I can't dig into it now.

Ammeter is also before the ignition in the circuit. Again, if it were bad the car wouldn't crank.

Facepalm added -

Arne, Steve - Thanks. The Ammeter still flicks to life while the car cranks in a sign that it appears to be business as usual up there. Still haven't had the heart to split that engine harness open yet, but I suppose that's coming. Anyone have a spare engine harness lying around for a Feb'70 240z? Hah!

Where is the 4 conductor connector on your Z with the red fried wire? Where do the wires on the non engine harness wire side of this connector go? No fuses blew? I am not sure I am interpreting your pictures correctly. I have a 1/'70 car and just looked and couldn't see a four conductor connector just behind the glove box near the right side of the car. Not sure this is worth looking at given the better advice you have already received.

Though more expensive than an ohmmeter what has helped me enormously to identify wires is a wire tracker that injects a radio signal with a warbling sound into any wire you clip onto. There is a small pen sized receiver with a plastic point that can be held close to and waved around different wires to figure out where the other end is. The one I have is made by GB Instruments and is model GET-4110K. You can lower the receiver sensitivity VIA a volume control on the "pen" to allow for more precise identification of the wire you are looking for. The PO for my car made wiring changes. I used the wire tracker to put the wiring back closer to stock wiring and labeled them so he can't confuse me again.

Mike

Edited July 17, 201113 yr by Mikes Z car