trying to do a harness update

[tasker]

using an older manual transmission dash harness, looking to incorporate the C4 transmission plug at the firewall. Have y 73 harness and was going to use that. Red/blue to ignition and black/red to reverse sound right? All the schematics I see show manual trans wiring.....sorry! Wiring is my nemesis!!!

 

[DirtDonk]

Yes. And no...
They are both related to the now-present Neutral Safety Switch.
The NSS interrupts both the Red w/blue "S" wire to the starter relay, and the Black w/red wires to the backup lamps. With your original manual trans, those duties were separated to a single column mounted switch for the backup lamps, and nothing interrupting the signal to the starter relay.

It's a square-shaped 4-wire connector that you can see the shape of by looking at the other end of your NSS switch.
You do have a Bronco C4 with the switch on the side. Correct?
If you end up not having a good time with the stock harnesses playing nice together, you can change the NSS connector to a more "universal" aftermarket GM Weatherpack connector and then put the other wires in a matching connector on the body side.

Paul

 

[tasker]

think I have it figured out....thanks Paul!

 

[tasker]

CAN SOMEONE please tell me the wiring for the neutral safety switch, harness side? it must make a difference which one goes to which....i know red/ blue stripe is for ignition and black/red is for reverse. I had them marked but cut the excess off to attach to "new harness" and never moved the markings! have a male and female of each color to work with and would like to only have to do this once...thanks!

 

[DirtDonk]

It doesn’t matter at all.
One is in, and one is out. The 12 V comes in on one from the ignition switch, to the neutral safety switch, and goes out on the other. When the neutral safety switch closes the contact, power flows through.
Same for both Backup and START.

If you’re using your own new connectors, then they are all usually protected. With the old style connectors, there was usually at least one, if not two that were “keyed“ so that you could only plug the connector together one way.
In those cases, the power-in from the chassis side was always a female contact so that you were less likely to short it out on something if the connections were separated.

 

[tasker]

That's what I kind of thought but wanted to make sure....thanks Paul!!

 

[Oldtimer]

question? I have my "new" dash harness pretty much sorted out except for two plugs.....a blue bullet and a very heavy black bullet connector.....thoughts?


View attachment 930941

Tasker,
I copied this from the "what have you done to your Bronco today" thread.

Blue bullet connector went to an emission control solenoid on carburator (anti diesel).


Heavy black bullet is probably the feed from battery post on starter relay.
There should be a Black/Yellow stripe wire that feeds thru loop on back of ammeter and plugs into it.
Other end of black/yellow wire goes to splice, connected to alternator & fuse box.
I stole these images from https://seabiscuit68.tripod.com/
I used 72 version, because colors seem to agree with what you have.

 

[tasker]

Pretty much done....with this anyway. Thanks for all the help!

 

[Oldtimer]

While harness is on workbench, pull the fuses and clean the rust off contacts in fuse box.
You don't want to try cleaning them after it is bolted to firewall (especially if you wear bifocals, like me).

 

[tasker]

already did.....old pic. But thanks for the tip!