Factory electronic distributor wiring

[71383bee]

So I've found one more engine wiring mystery on my 73 challenger with the 70 383 unit.
There is a light brown wire that comes out of the fuse panel and comes through a rubber grommet by itself directly above the steering column. This wire runs across the firewall to the passenger side top of the engine, and then ends in a single rubber bullet style connector there.
This photo is of the engine before I restored it and I've put the green arrow on the connector in question. In the old photo it has a male bullet connector, also light brown wire that was then badly spliced into the mess that was an early aftermarket coil on the inner fender.
Now that I've removed all of that I don't have a matching plug for it, nor do I appear to be missing anything, and my colour wiring diagram doesn't show this wire.
Can anyone tell me on a 73 where this wire should go and what it's feeding?

Hey Todd.  That's the tach wire.  It too had its own splice at the corner of the bay.  It needs to be extended to the + side of the coil.  Ill try and attach a picture of how mine is.  It was re-spliced in its life downstream of the stock connector. 

My repro harness is from Year One from M&H it's a real nice piece.  Cheap insurance IMHO.  You now have my original one that was re-spliced for the hot alt wire.  It worked though!  I got around 3-4k miles on it like that! 

I talked to Bill Even's once about these harnesses as I needed the trans and ac harnesses and he said that he doesn't sell the 73 and up style with the extra bulkheads as it just adds more resistance to a system that's been shown over time to have trouble.  He said if its a stock repro he'll make one but its a custom upcharge. I get why the factory did it but I've seen a few of these fried at this spot due to the additional resistance. 

If your this far in Todd I recommend you run a 10ga bypass wire from the alt. to the relay to take load off of those older wires. 

[JS29]

I do believe the tach lead go's to the negative side of the coil.   

[fireguyfire]

Ok, so it makes sense to do away with the connector to reduce resistance; by the way Chris, your old harness was a huge help in rebuilding my butchered one!
So does this tach wire go to the + or the - side of the coil?

[71383bee]

I do believe the tach lead go's to the negative side of the coil. 

Oops my bad I see that now.  - is correct for tach.  It is also supposed to be gray but mine is tan-ish brown.  I recall going through this exercise before when i changed out my wiring.  I remember the color fooled me for a bit.  That wire is not in the engine forward harness.  it is its own deal.  Not sure if this was that way for a 72.  Ill correct my post!

The picture up top is how that corner looks on my 73 for reference now.  The bottom two is the corner in the process of changing out.  Hope they can help. 

[fireguyfire]

Thanks[emoji106]very helpful

[fireguyfire]

One more question since I've asked every other one about my butchered engine harness: there's a blue wire with a plastic connector that terminates just about at the bottom of the passenger side of the carb (I'm going to a sniper EFI setup).
I'm assuming this would have been the electric choke wire?

[Bullitt-]

One more question since I've asked every other one about my butchered engine harness: there's a blue wire with a plastic connector that terminates just about at the bottom of the passenger side of the carb (I'm going to a sniper EFI setup).
I'm assuming this would have been the electric choke wire?

Correct

[71383bee]

Yep. It goes to a choke control unit that looked a bit like a ballast resistor. From there there was a wire that went to the choke well.

It gets hot on the run side of the ignition so it can be used for an electric choke if your using one.


Sent from my iPhone using Tapatalk

[kawahonda]

That wire on my car goes into the curb idle solenoid currently.

I was hoping it could be also used for an electric choke....HOWEVER...

That wire is getting juice from the alternator, so it will go above 12V during running. Is that still OK for an electric choke?