HELP !!! I need help please

[anlauto]

I do not  think some people are realizing that it is a 392 conversion and you are not going to be using the factory starter relay and no more ballast resistor for the ignition. Correct?

100% correct....nothing factory under the hood is left...the new engine harness(s) include their own fuse box with the relays to even control the fans the fuel pump, etc...

[Ek2aar]

The new 392 crate harness, has the starter power wire and the starter solenoid wire as part of the engine harness. It makes no mention of the factory  starter relay that mounts on the inner fender, so I figured I could eliminate that altogether and the new harness will take care of it's purpose

The "yellow" wire I have circled in my second picture, comes from the ignition switch in the column, directly out through the bulkhead and to the starter relay. I don't know when it "has power" ??? Does it have power at all ??? or does it take the ground from the transmission and send it back to the ignition switch ?

The yellow wire is the a factory ground, that runs through the nuetral safety that you will not be using if you use the tremec 2 wire nuetral safety.
I have used the tremec nuetral safety the same way you are planning and it works perfectly.
You will not have to push on the clutch to start it anymore,  the shifter being in the nuetral position makes the contact.

[anlauto]

Excellent, thank you

Now "IF" I had a stock original car here I would get out my trusty test light , find a good ground inside the car, locate the factory ignition harness at the column and do the following tests

Test the three wires in question YELLOW, BROWN, and BLUE at the steering column for the following:

A. With the key off, does any of the wires have power ?
B. With the key on, does any of the wire(s) have power ?
C. Cranking the engine over, which wire(s) have power ?
D. With the engine running, and the key returned to the on position, which wire(s) have power ?

The test would have to be done individually for each wire, recording the results.

I think if I knew the answers to these questions, I could determine which wires I would have to connect my two new wires to. HOWEVER if one of my new wires has to be connected to two of the existing wires at the same time as Sheldon suggested...then I'm completely confused again...

...and I don't have a stock original car here, so I'm SOL unless....

[Ek2aar]

I am no expert , but if you connected both the blue and brown together,  there would be no separation between the starter crank signal and ignition.  Therefore the starter would always be engaged....🤷‍♀️

[dodj]

A nothing
B blue wire
C brown wire
D blue wire

[anlauto]

Did you do the tests or just make assumptions ? If you took the time, THANK YOU very much 

But just to be clear....

C. When cranking the engine ONLY the brown wire has power and NOT the blue or yellow at the same time ?
D. With the engine running, ONLY the blue wire has power and NOT the brown or yellow ?

[dodj]

Yellow is never power. It is a switched ground for the starter relay. edit Sorry Alan, my mistake. Like dmod said yellow is a start wire. The yellow/brown is the switched ground.

C. When cranking the engine ONLY the brown wire has power and NOT the blue or yellow at the same time ?
D. With the engine running, ONLY the blue wire has power and NOT the brown or yellow ?

Correct. On a stock ebody. edit Yellow and brown will be powered at the same time so what I wrote below is a non-issue.

The issue you are going to have is the LB/TN wire requires the brown wire. Power when cranking.
The PK wire requires power when cranking and running, which would be the blue and brown together. But if you connect them together(like i said earlier), you will no longer have the brown wire as 'only when cranking power'. Together they become cranking and run power. You could use a relay to maintain the seperation I think.

[Dmod1974]

LB/TN wire to factory Yellow ignition switch START wire

PK to factory Blue and Brown ignition switch (ballast resistor bypass and normal ignition) wires teed together

DG/OG clutch interlock wire to factory dark green (manual) or brown/yellow (auto) starter relay ground IF you using a neutral or clutch safety switch.  If not, ground the DG/OG wire.

[Dmod1974]

There is zero issue tying the blue and brown wires together guys....  Yes, there are 2 wires hot in start - for a very good reason.  One sends 12v to the starter relay, and the other sends 12v straight to the ignition coil bypassing the ballast resistor during crank ONLY to ensure the coil has enough voltage to make spark.  They are NOT connected together at all, and the switch schematics confirm this.

When you let off the key, the other ignition wire takes over and sends power to the ignition coil via the ballast resistor so it doesn't overheat.

You're not using a ballast resistor, so tie them together so the PCM doesn't shut off as soon as you let off the key because it will if you don't.


Also, the yellow Start wire is NOT a ground.  The NSS or clutch switch provides ground.  The ignition switch only switches 12v.

[anlauto]

Okay so.....I have no more wires in the engine compartment. I've removed the wires in question from the interior side of the bulkhead. The three wires in the main dash harness go directly from the bulkhead to the ignition switch in the steering column with only the one large connector at the column.

If I'm understanding you correctly....Starting at that large connector, I can take the existing yellow wire, connect it directly to the new  LB/TN wire in the new 392 harness. I can also take the existing brown and blue wires from the same steering column connector and connect them together and connect them directly to the new PK wire ?

...and I should be good to go ?

Does that sound right @Dmod1974

Before I cut into and start soldering, does anybody else AGREE or DISAGREE ? 

[Dmod1974]

Okay so.....I have no more wires in the engine compartment. I've removed the wires in question from the interior side of the bulkhead. The three wires in the main dash harness go directly from the bulkhead to the ignition switch in the steering column with only the one large connector at the column.

If I'm understanding you correctly....Starting at that large connector, I can take the existing yellow wire, connect it directly to the new  LB/TN wire in the new 392 harness. I can also take the existing brown and blue wires from the same steering column connector and connect them together and connect them directly to the new PK wire ?

...and I should be good to go ?

Does that sound right @Dmod1974

Before I cut into and start soldering, does anybody else AGREE or DISAGREE ? 

Exactly....  The brown wires only purpose was to provide a full 12v bypass around the ballast resistor to the coil during cranking - nothing more.

On a carb car the milliseconds that the 12v feed to the coil goes "dead" before the RUN circuit takes over when you let off the key doesn't matter since the engine is already firing.

On an EFI setup if will cause the PCM to reset and shutdown though.

I'm not just theorizing; I had to wire my car this exact same way when I was running Megasquirt EFI too.  It'll want to start and then die the second you let off the key if you don't jumper those wires together.

[Dmod1974]

Also, to be clear - you're still going to connect the blue wire to the fusebox as well, right?  That circuit powers up all of the ignition circuits there as well.  You're going to splice the brown, blue, and new pink wires together but cannot just cut the blue wire and only connect it to the pink.  Splice into it.

The pink wire doesn't carry any real current; it's just a relay turn on circuit.

[anlauto]

Also, to be clear - you're still going to connect the blue wire to the fusebox as well, right?  That circuit powers up all of the ignition circuits there as well.  You're going to splice the brown, blue, and new pink wires together but cannot just cut the blue wire and only connect it to the pink.  Splice into it.

The pink wire doesn't carry any real current; it's just a relay turn on circuit.

On a stock application the blue wire goes directly from the ignition switch connector (shown above) to the bulkhead --- Through the bulkhead in the engine wire harness...breaks up and feeds the ballast resistor, alternator and voltage regulator, etc....

With the 393 crate Hemi harness....it uses NONE OF THAT.... so I'm a little confused by your above statement ? I would think that hooking the blue and brown wires to the new pink wire, that would give the 392's computer the responsibility of  the "circuit powers up all of the ignition circuits" ?

[anlauto]

I'm sure hundreds of people have installed these engines using the crate set-up from Chrysler...it can't be that hard to figure out.

@MoparDave  Dave you guys have done these conversions, any input on my wiring question ?

@Blake@diyhemi.com  Any thoughts ?

[Chryco Psycho]

So can you shed some light on these two wires in question ? I would like to hear from everybody before I blow things up  :c

Well yes of course I could , it is simple circuitry