+electrical pics / Who has a 12/73 build or early 1974 Bronco +

[Broncoblood]

I have a December of 1973 build Bronco, basically 1974 with all the original wiring and engine under the hood. unfortunately I had an engine fire and I cannot identify the wiring harness pig tails and plugs that I have. The main one I am trying to identify is the harness that comes out of the center of the firewall behind the driver side valve cover? that part of the harness I believe has 3 plugs? one going down to the neutral safety switch, once going to the electronic ignition and one red one going to the temp sending units oil / water. I know some years have a red plug there that is all one female plus and some others have a single male and the 2 or 3 female holes next to it?

anyways, my question is, could someone with the same year Bronco send me some detailed pics of the wiring harness plugs and colors and routing from firewall to the distributor and all the other spots and how the 3 or plugs should look?
I hear it makes a difference and I will mention that mine is a Duraspark, my Duraspark has 7 wires instead of 6 and that 7th wire is purple. Also my emergency flasher switch is a button on the side of the steering column and mine is an automatic.

I think that's all the description I need to identify the model.

any pics will help, thank you

 

[Steve83]

Click this, read the caption, and the NEXT few:



Also click the 74 wagon link in my signature, and browse the As-Was album. It's very similar to yours, but everything was bedlined, so colors are generally NOT visible.

 

[Broncoblood]

I appreciate it.
The diagram is a little overboard and cannot tell if the red plug was full or partial?
also I didn't see a Duraspark on yours?
thank you for help tho

 

[DirtDonk]

You might at least try Steve's 75 diagrams to see if that gives you a little more detail to work with until someone comes up with under-hood pics for you.

Steve, I see that your '74 is mated up to '73, but you might update it to mention that some '74's (at least in CA) had Dura Spark ignitions. I forget which color, but we can find out easy enough if Broncoblood's is original and still visible after the fire?
Might have to lump the '74's in with the '75-'77 then.

Speaking of that Broncoblood, if you did not already, check out Steve's 75-77 diagram and see if that gives you some more detail.
The issue I think could actually still be that Red plug if the Dura Spark in yours is wired slightly different from the others.
In Hayne's manuals, the '74 is it's own year, the '75 and '76 are together, and the '77 is again it's own diagram.

Check out the other ones though, to see if they help.
I see lots of connector details, but still don't see that red connector. Maybe this will be the time we get some new info to Steve to update is stuff again.

Good luck.

Paul

 

[Broncoblood]

all good info but I would really love to see some late 73 early 74 pics of the Duraspark, ignition, water and oil temp fee harness and plugs?

 

[Steve83]

The differences for '74 are noted on that diagram, similar to what the source (Seabiscuit) diagram showed. Look in zone K3 for the ignition, and simply continue through the NEXT several '73-74 diagrams to get to the '75, which shows that detail.

 

[DirtDonk]

Closest I've found so far. Hard to see the details at this angle, but also an early '76 model, so not exactly what you need.

 

[DirtDonk]

Late '73 model (5/73) so still points ignition and not the same connectors:

 

[Broncoblood]

I appreciate those pics and that info on zone K3.
The 76 red plug appears to be the oblong n one that surrounds all the wires and the mid to early 73 one looks like it is most likely the style I will need with 3 female and 1 male? I still think those both are too early and too late to confirm what I need but I will look into that K3 zone stuff and hope I find the harness and tails that I need that I am still in search of?? thank you

 

[johnbeck]

Paul posted the 5/73 engine picture. My 2/73 has the same firewall red to black engine connectors. Where does the red with white, white(or yellow) with red center wire, and the largest light brown or orange wire go? The connections and engine wires are pictured on Paul's last post, the discussion has been on where the firewall to engine wires go, I would be extremely grateful if someone could identify the destination of those wires. I apologize if my request is considered to be a wayward diversion. Establishing another post establishing precisely the same information would require much more time and energy from our gracious contributors. Thank you.

 

[DirtDonk]

No problem John. Those are just the basic top-of-the-engine wires if I remember.
If I have their locations and functions correct in my mind:

Engine side of connector:
1. The Red w/white wire is for the Water Temp sender.
2. The White w/red is for the Oil Pressure sender.
3. The other should be the Red w/green for the ignition coil, with a Brown wire spliced into that same circuit on the body side of the harness.
Double check yours to see what color they are please, and let us know. I've seen some Fords where the Red w/green is some other color completely, reminiscent of the resistor wire color. And that's what yours sounds like (puke brown, faded pinkish) so I'm curious.
Check it out to see if along it's line it says something like "do not splice. resistance wire" or words to that effect.

The engine side plug wires go to the senders and the ignition coil.
The body side plug wires run through the firewall for most of the wires. I forget where the Brown wire is routed to get to the starter relay for each Bronco, but it might vary by year. The '73 probably also runs into the cab, but then back out on the passenger side firewall to the relay.

The Red w/white and White w/red go directly to their respective gauges, the Red w/green becomes the resistor wire under the dash and runs directly to the ignition switch, and the Brown wire runs directly to the "I" terminal on the starter relay.

Paul

 

[johnbeck]

Thanks Paul. Red/white =water temp. White/red =oil pres.(White/purple on body side of connection). Where does the Puke Brown, "do not spice" wire attach on the engine?(TPO cut and spliced a small gauge wire on to the "do not splice" wire -is that a problem? What attaches to the single blue connection on a blue wire, part of the same thru the firewall grouping? Thanks again. My rebuilt 302 has been sitting on the garage floor while I finish the wiring and a few other items. You and W.H have been so helpful!

 

[DirtDonk]

Well maybe we should have started another thread after all!;D

Red/white =water temp.
White/red =oil pres.(White/purple on body side of connection).

Probably just faded to purple. That or the manufacturer had a bad batch of dyes. Happens...

Where does the Puke Brown, "do not spice" wire attach on the engine?

Ignition coil, positive side.
This is the ignition coil power through a resistor to drop the voltage to more around the 7-9v point.
Typically the resistor part is entirely under the dash and the part under the hood is regular wire. We may need to do some more testing, just to be sure what you have.

(TPO cut and spliced a small gauge wire on to the "do not splice" wire -is that a problem?

Could be, but we need a pic of this splice. Does it look like a pro did it, ore not? And let's see that wire anyway. Did you see the printing on it?
With luck it's just normal wire that's colored like the resistor wire. But let's see what you've got.

What attaches to the single blue connection on a blue wire, part of the same thru the firewall grouping?

Sounds like the carburetor's "anti-dieseling" solenoid.
Do you still have one? Stock carburetor, or aftermarket?

My rebuilt 302 has been sitting on the garage floor while I finish the wiring and a few other items. You and W.H have been so helpful!

Thanks. Glad we could help, and thanks for helping us too!
Have you kept it covered to keep dirt and grit out? At least moisture is not a huge issue when in the garage (vs sitting outside), but still something to be careful of over the long term.
Got pics of your setup?

And one last wire we have not discussed that your '73 should have present, is the White w/black trace "stator" wire.
On a '73 it's only purpose was to power up the factory automatic choke on the carburetor. One end is connected to the choke and the other connects to the alternator's "STA" terminal on back.
This would normally not come through the firewall I'm pretty sure. It would just come up from the alternator to the carburetor directly, perhaps running along the passenger side, or perhaps running straight up the engine from the alternator. Been awhile since I traced one, but keep your eyes open for it with the alternator wires.

If we need to discuss it some more, let's start another thread and we can transfer some of these posts over to it. Rather than keep adding to Broncoblood's thread about '74 wiring.

Paul

 

[johnbeck]

Thanks Paul. I'll switch to a new thread

 

[Scoop]

January 1974 build. Stock - this has never been touched or apart.

 

[Broncoblood]

That is perfect
Thank you scoop, I will PM you.
I appreciate the pics

 

[Broncoblood]

I found a 1974 with Duraspark,
it has 4 connectors coming out of the firewall.
I am still looking for a good used harness if anybody has one?
JeffsGraveyard had some 71-72 original ones replicated but I need 74.
anybody got anything? or know of anybody?