73 Barracuda engine wiring harness diagram

[JunkYardFind]

Just received my new engine wiring harness from Evans Wiring. Probably a straight forward job once I get going but I would be grateful for any tips or possibly a diagram to follow in case I cannot simply unplug the old wire and plug in the new. I see the whole car wiring diagrams that look pretty complicated. I there a separate diagram for each harness that plugs into the bulkhead? I am going to replace each one....one at a time....very slowly.

[MoparLeo]

I never had an Evans Harness. They are not labeled? My M&H/ YearOne is. Contact Evans first.

[Rich G.]

I've used Evans on all my cars. Just did a 73. It's pretty straight forward. Just lay it out across where it should go and they fall in place. Any questions just ask. Those laminated wiring diagrams they sell on EBay are very easy to read. (Classiccarwiring) FYI if you have a/c that's a separate harness.

[Shane Kelley]

I've used Evans on all my cars. Just did a 73. It's pretty straight forward. Just lay it out across where it should go and they fall in place. Any questions just ask. Those laminated wiring diagrams they sell on EBay are very easy to read. (Classiccarwiring) FYI if you have a/c that's a separate harness.

  Installed plenty of Evan's engine harnesses. Pretty much identical to factory and very straight forward. If you get in a bind just post a pic and a question. Somebody here will know the answer.   

[JunkYardFind]

Okay, sounds good! Lets start with what's different on the harness.
> on the Evans tab there is a blank on the bottom left of the tab (fig 1). On the OE there is a blue wire leading into the harness. (fig 2) Where/what is the blue wire I am missing?
> On both harness there is a lead out immediately after the main plug (fig 3) this was not connected to anything on my car it was just hanging there. Where/what is this?

Thanks....gonna a be a few questions on this job. Not to familiar with wiring but have already done the bypass and headlight relay fixes. Both really easy. Hopefully this will be too once I get going.

[JunkYardFind]

Was moving along pretty good and ran into this (left fig 4) It is in the OE engine harness pretty close to the electronic ignition plug. I should mention here, my car is A/C.
It plugs into what looks very much like another bulkhead connector type plug (right fig 4)
It has a nice burn in it also. (fig 6) Although, I think this burn has been there for YEARS and no noticeable problems that I can tell.

This attachment puts me a dead stop as the Evans wiring does not include this female plug.
> The usual what is this plug/where is it going? It sits along the back of the pass valve cover and leads to ???

[Rich G.]

Hopefully you can blow this up.

[JunkYardFind]

So, progress! Tore into both sides of the "second" bulkhead connectors.
It turns out that connector is not really useful, so far anyway.
All the wires I trace out of it are indeed on the Evans wiring. Anyone have an idea if this is stock? Or more likely someone even worse than me (SCARY) did some wiring in the 70's? Dunno, let me know what you think. Ran out of daylight today. Update tomorrow.

[JunkYardFind]

Also, for those wondering if they should replace their wiring...here are some better pics of the surprise I found. (fig 7-9)
It seemed to have no effect on the car at all. I will figure out what wire it was tomorrow hopefully. Oddly, this seems to be some sort of bypass in the engine harness, of no use that I can figure out.

Luckily the Evans wiring will fix all this!

[71383bee]

That's the in line stock bulkhead connection on the right rear valve cover. They were on 73 and up cars. Evans purposely does not reproduce them unless you custom order it. M&H does reproduce it. It's not needed. All pre 73 cars were built with out them and run fine. It's just another connection that generates heat. With the ammeter bypass in place the risk is lower.

The a/c harness has individual wires that plug into I believe the engine forward and the neutral safety  bulkheads. If your not using the AC you will be fine.

I redid all of the engine forward harness on my 73 a year or so ago and went through similar issues.

Evans makes a quality harness and he is a great resource. Bill is usually reachable on the phone if you have issues.


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[71383bee]

On your stock bulkhead connector with the missing wire is the #20 post for ac. It takes a dark blue wire to the pressure switch. There should also be a dark green wire that goes to post 4 on the NSS harness.

I believe the connector near the bulkhead goes to the brake warming lamp system.

Is yours setup for a stock 4 pin ballast? 


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[JunkYardFind]

On your stock bulkhead connector with the missing wire is the #20 post for ac. It takes a dark blue wire to the pressure switch. There should also be a dark green wire that goes to post 4 on the NSS harness.

I believe the connector near the bulkhead goes to the brake warming lamp system.

Is yours setup for a stock 4 pin ballast? 

@71383bee
First off, thanks for the info! Couple of clarifications needed.
> I will likely just trace the Blue wire but what/where is the pressure switch.
> What/where is the NSS harness.
> Not sure what you mean by "stock 4 pin balast" please forgive my ignorance!

[Rich G.]

Pressure switch is on the a/c drier, 4 pin ballast resistor is the white thing on the firewall and the nss ( neutral safety switch harness)  is the separate one that goes down to the transmission.

[71383bee]

Pressure switch is on the a/c drier, 4 pin ballast resistor is the white thing on the firewall and the nss ( neutral safety switch harness)  is the separate one that goes down to the transmission.

Thanks Rich!

You got it.  The Ac harness is separate and basically plugs into the other bulkhead blank spots. 

On the bulkhead connections the NSS is the smaller bottom 4 prong harness to the lower left (if looking at it).  The upper one goes to the 3 speed wipers.

I attached a picture of how the engine forward and NSS harnesses are tied together when you have AC.  I replaced them all, engine forward, Trans (4 speed and auto uses a similar harness), and AC. 

[JunkYardFind]

More progress! Thanks for the help here.
I am almost wired, just have 3 wires I need verification before I attempt to start her up.

1. On the Evans harness there is a Gray wire that leads just below the 4 pin ballast resistor. (Fig gray1) There is a natural plug right next to it so I am  pretty sure this one goes there. The Evans gray wire reaches but just barely, I will have to extend the wire about an inch to reach the connect. Also, what is this connection? It leads to a cylindrical piece that has a green wire attached, which is not connected from long ago.

2. Next is the Brown wire that leads out with the alt wires. (fig brown-alt1) I have no natural connection for this. It also looks like a VERY small connector within the wire. (fig brown-alt2)

3. Lastly the blue wire that matches perfectly with the AC compressor connect (fig blue AC2). Likely plugs here but I am confused as the Blue wire in port 20 of the bulkhead connector is not there. It matches too well for it not be correct I would think. I will contact Evans on this if there is any doubt.