What is the pinkb/grn stripe wire goes to pass side cant see where it goes. But its burning hot with key on and engine running or not. Trying to fig why my gauges dont work and came accross that wire... voltage reg good in regards to gauges fuse and block good.. if that wire is part of the dizzy stuff it may be why I have a stumble...

 

If it's pink and it's warm, it's probably the resistor wire that feeds the coil. It's normal for it to get somewhat warm during normal operation, but if it's getting hot enough to be a safety concern, you might want to check to be sure the previous owner didn't tap into the coil + wire to power something else (e.g. an electric choke, etc.)


It should have 1.3-1.4 ohms resistance over the length of it.

 

It get pretty hot id like to check it, I put this harness in and it wasnt molested, but just to be sure wheres it come out at? It leads to pass side my coil loom is on drivers side.

 

The pass-through in the firewall where the harness goes through is the one towards the passenger side. Inside the harness, under the hood, the resistor wire should terminate in a splice that goes to the red/green wire at the + side of the coil, and the brown wire to the "I" terminal on the starter solenoid should tie in there too.

 

So after pulling the ignition out I found that the red w grn stripe wire had melted its insulation. To be honest I tried to read the schematics on fortification to fig out what that wire is but Im having a hard time with the matching numbers thing, I can read basic wiring diagrams, but that diagram isn't easy for me to read.

Also do you happen to know what on the ign provides power to the cluster, I found I have no power to the cluster except lights no gauges.

 

Sooo I said "leeerrrooooyyy jeeennkiiins" and took all the tape off the harness (tip: zip tie the ends where you dont want it to come off and do surgery between)

Found this guy (the broken wire) which after tracing the print board led to 12v power to the IVR. I think gauge prob is solved. On to that melted wire which supplies power to the fuse block... find out why it melted.

 

I have a question I need clarified....

I'm in the process of getting ready to tear open the wiring harness under the dash to inspect the "resistor" wire that goes to the coil +, as I'm only getting 3 volts to the coil.... Which side of the wiring loom starting at the ignition switch should I be opening up to find the resistor wire? I was assuming it was in the part of the wiring loom that goes from the ignition switch, behind the instrument cluster and out the driver's side firewall by the power brake booster & ignition box. But after reading this post, am I correct to assume this "resistor" wire is in the wiring loom that goes from the ignition switch over to the passenger side and exits through the firewall into the engine compartment by the heater box fan motor???? Just need to know which side of the wiring loom I need to open up to find this "resistor" wire that powers the coil +.

Thanks for the help...

 

Pink/ grn wire goes to pass side my harness is opened up atm, a wire may back track to the driverside to coil but Iunno...

 

Thanks for the advice. So I guess I'll open up the wire loom that heads toward the passenger side...

 

Yes, that's correct. I just re-bundled my whole harness a month or so ago. The resistor wire runs towards the passenger side and through the big grommet that goes through the firewall over there. Then once under the hood, it doubles back towards the driver side and then up to the coil. I think they did it this way to make it long enough to get the 1.3 ohms resistance they were aiming for.

 

Thanks for that info....Question, where does the starter bypass wire splice into the resistor wire? Is the splice in the wire loom under the dash or under the hood in the engine compartment? I don't want to open up the wiring harness under the dash if the splice is in the wiring harness under the hood (and visa versa). This info would really help....Thanks.

 

That splice is under the hood.

 

I need some advice again. I opened up the wiring harness tonight and found the pink wire. It starts under the dash behind the glove box and goes over the heater controls, behind the instrument panel and then towards the firewall where the wiring harness goes through the firewall on the drivers side. Only it must terminate before it goes through the firewall because I don't see the pink wire coming through the firewall......So am I correct in assuming I can just clip the pink wire anywhere I want (like right behind the instrument panel where I found it?)

Ok here's something that threw me for a loop and has stopped my progress until I can get some advice.... I tested for 12v at the red wire in the plug connector that plugs into the factory ignition box and there is NOT any voltage whatsoever with the key on!!! I even tested for voltage when cranking the motor and still nothing!!!

Question....Even if the pink wire is damaged, I should still have 12 volts at the red wire, correct or is that wrong? I assumed I'd have 12v at this plug, but nothing. However, with that said, I do have 12v on the white wire. Am I supposed to have 12v at the white wire with just the key on and not running? Why do I not have 12v at the red wire, but I do at the white wire? Is it because the pink wire is bad?

I'm going to hook up a ballast resistor in place of the pink wire for the time being so I can get the truck running. I'll replace the pink wire later once I get this figured out. I haven't cut the pink wire and hooked up the ballast resistor yet because I'm not sure what this means by not having 12v at the red wire in the plug. I need some advice on what to do next and what this all means before I go cutting wires. What do I do now?

 

The resistor wire and the red wire to the ignition module should run in parallel from the ignition switch. Are you getting 12V to the ignition switch?


If you're replacing the resistor wire, you'll need to find the splice where it ends in a red/green wire that goes to the coil. The length matters to get the resistance correct, so you can't just splice it any which way. If you're just removing it and bypassing it and using a ballast resistor, then you'd want to cut it off at the switch end, and splice back in somewhere near the coil where it's a standard red/green wire.


If yours doesn't pass through on the passenger side, maybe they changed the routing between '74 and '78 - sorry to lead you wrong.

 

Yes, I'm getting 12v to the ignition switch. I'm even getting 12v to the "I" terminal on the starter solenoid. Just not at the red wire in the plug nor on the coil wire.

I was planning to bypass the resistor wire for now by plugging in a wire from the original ignition box plug (assuming it was getting 12v) and running it to a ballast resistor and then to the MSD ignition box (red switched wire). I wasn't going to use the original coil wire at all, per advice on here.

Here's the diagram I'm following.... https://www.google.com/search?q=dura...ZN8oKqo7y5M%3A

However, the brown wire on the "I" terminal doesn't plug into the coil terminal, I assume it splices into the resistor wire somewhere.

So let me understand this....if you said the red wire that goes to the ignition box plug runs parallel to the pink wire, and I'm not getting any volts to the red wire or at the coil green/red wire (via the pink wire), then that means I have two separate problems???? I put the old ignition switch back on as a process of elimination (before I tested the red wire at the plug tonight). So maybe I'll reinstall the new ignition switch and test the red wire again and see what happens. But with either switch, I still don't have power at the green/red coil wire.

This couldn't be happening at a worse time. I'm getting ready to move this weekend and I can't get my truck running!!! It's looking like I'm going to have to rent a car trailer and tow it to the new house. I was hoping to use it to help move. Hopefully I can get this figured out with your help....