Trying to patch cut wires back together

[katwalk]

My ‘69 currently has no lights in the rear (brake, turn, reverse, etc). In going through all the wiring I have found a plug in the engine bay (pic 1) and some cut wires under the drivers seat (pic 2). Process of elimination tells me this may go together, but the wires are different cooors and don’t exactly match my wiring diagram. Any guidance on what I might be looking at?

 

[DirtDonk]

Where do the wires in the second pic go?
Considering that they ARE in fact the same colors as the ones by the firewall, or at least look to be from here, then it's a good bet that they are the same.
Either the colors have faded on the ones under the hood, but not further back, or the wires under the truck are newer.
Where were they cut? And do they reach each other?

From the factory, the colors need to match exactly, of course. Because they are not broken up into segments, but are one piece all the way from that firewall bundle (should be a connector?) back to the driver's side frame rail, and to the back lights. From the driver's side they continue over to the passenger side lamp, along the body panel under the tailgate.
Are there any wires in the back still? Wires coming out of the lights and then running along next to the gas tank that you can see?
Got a pic of the rearward wires further back? Got a pic of the wires in the first pic, but without the hidden connector or any cuts hidden by your hand?

Must be a trick of the pic, but the ones in the second pic look newer and of a larger gauge. Is that a visual trick, or are they essentially the same?

Paul

 

[Oldtimer]

Test the 4 wires at the firewall. Should be Left & Right turn, running lights, and backup lights.
From factory, there was a connector at bulkhead, and you should find another connector on top of the driver side frame rail behind rear axle. You need a harness from the fire to the rear connector. I think the Bronco vendors, or Dennis Carpenter sell this frame harness. I would find a 4 pin connector set to wire in at the firewall, and run 4 wires down the frame, and splice to connector by rear axle.

*posted from a moutain top in the Eldorado National Forest, so can't provide any pictures of my harness.

 

[serial car restorer]

Brown is the tail lights, license light and side markers. Yellow (sometimes with a black stripe) is the left turn signal/brake light. Green is the right TS/brake. Backup lights were black with a red stripe.

One of those wires in the firewall pic looks burned to me...

 

[BroncoLew]

My ‘69 currently has no lights in the rear (brake, turn, reverse, etc). In going through all the wiring I have found a plug in the engine bay (pic 1) and some cut wires under the drivers seat (pic 2). Process of elimination tells me this may go together, but the wires are different cooors and don’t exactly match my wiring diagram. Any guidance on what I might be looking at?

Link to early Bronco wiring diagrams

Here is a link to some early Bronco wiring diagrams I found online. Let me know if they aren't helpful and I can find my USB stick that may have a better one.

 

[katwalk]

Thanks all.

@DirtDonk
- The cut wires under the driver side go to the rear taillights
- it may look like it in the pic, but the cut wires and the engine bay wires are different (if they were a match, I would not have the confusion that I do)
- Engine bay wires- yellow/black, orange, green and black or purple (hard to tell)
- Under driver seat- yellow, black/red, brown and green
- they do not reach each other
- I am in NJ for work this week so will climb around under the rig when I get back to town


@Oldtimer
- I will trace the wires underneath when I get back to town
- thanks for the lead on the harness - Wild Horses has one for $165

@serial car restorer
- it is not burn. It looks like sticky residue form some previous wire wrap

@BroncoLew
- thanks for the link. I had run across that before and have referenced it but it does not tie exactly to what is on my rig.

Again, thanks for the time you guys took to respond.

- Farrell

 

[BroncoLew]

Thanks all.

@DirtDonk
- The cut wires under the driver side go to the rear taillights
- it may look like it in the pic, but the cut wires and the engine bay wires are different (if they were a match, I would not have the confusion that I do)
- Engine bay wires- yellow/black, orange, green and black or purple (hard to tell)
- Under driver seat- yellow, black/red, brown and green
- they do not reach each other
- I am in NJ for work this week so will climb around under the rig when I get back to town


@Oldtimer
- I will trace the wires underneath when I get back to town
- thanks for the lead on the harness - Wild Horses has one for $165

@serial car restorer
- it is not burn. It looks like sticky residue form some previous wire wrap

@BroncoLew
- thanks for the link. I had run across that before and have referenced it but it does not tie exactly to what is on my rig.

Again, thanks for the time you guys took to respond.

- Farrell

Hope this helps. I had a lot of wiring issues on mine and ended up taking it to a shop and had a new harness installed. Chasing electrical gremlins is never fun.

 

[Oldtimer]

The above connector that BroncoLew circled, does not show the forth wire it contains. The missing wire is orange and is for main tank fuel level sender.
On the right edge of schematic he posted are the frame connectors behind rear axle.

 

[DirtDonk]

- it may look like it in the pic, but the cut wires and the engine bay wires are different (if they were a match, I would not have the confusion that I do)
- Engine bay wires- yellow/black, orange, green and black or purple (hard to tell)
- Under driver seat- yellow, black/red, brown and green

Part of the confusion might be that many of our wires change colors drastically over the years. More than you might think or expect.
So a Black, or Brown could turn to Purple. A black stripe might disappear from a Yellow wire, or it might never have been there in the first place, depending on how the harness manufacturer handled problems. At least the Green seems to have survived.
Best bet (aside from the next comment) would be to test the wires in the engine bay with a volt-meter. See what you can find with the key on, shifter in reverse. Key on, looking for pulsing voltage on the Orange wire. Key ON, with the turn signal switch in one position, then the other.
Pretty straightforward most likely. Except for this next bit.

- they do not reach each other

Ok, so someone either hacked up the harness, or perhaps they simply cut it and then the wires got re-routed to a point that they no longer meet up.
Either way, you either need to patch 'em, replace 'em, or get a new harness. At least for that section.
Speaking of which... What's the general condition of the rest of the harness?

Paul

 

[katwalk]

Part of the confusion might be that many of our wires change colors drastically over the years. More than you might think or expect.
So a Black, or Brown could turn to Purple. A black stripe might disappear from a Yellow wire, or it might never have been there in the first place, depending on how the harness manufacturer handled problems. At least the Green seems to have survived.
Best bet (aside from the next comment) would be to test the wires in the engine bay with a volt-meter. See what you can find with the key on, shifter in reverse. Key on, looking for pulsing voltage on the Orange wire. Key ON, with the turn signal switch in one position, then the other.
Pretty straightforward most likely. Except for this next bit.

Ok, so someone either hacked up the harness, or perhaps they simply cut it and then the wires got re-routed to a point that they no longer meet up.
Either way, you either need to patch 'em, replace 'em, or get a new harness. At least for that section.
Speaking of which... What's the general condition of the rest of the harness?

Paul

Thanks Donk. I have given the wiring a cursory look over so far (trying to get it running right is has been my first priority, wiring is next) and it all looks pretty good (no burnt or crusty wires, much of the loom looks intact and in good shape. I think I am going to go ahead and buy the harness that goes form the firewall to rear lights/plug and go from there. Looking forward to the long holiday weekend so I can dig deeper into this rig - cant wait to get it on the road!

 

[Oldtimer]

Back to the flat lands, where I have access to my computer.

Firewall connectors (added MP-150 for Aux Tank):

Rear Frame connectors:

Seabiscuit68 Schematic:

Combined:

 

[katwalk]

@Oldtimer you are a rock star. This will help a bunch when I get back home and can be around my Bronco. Thank you.

 

[aolshove]

View attachment 966613

Hope this helps. I had a lot of wiring issues on mine and ended up taking it to a shop and had a new harness installed. Chasing electrical gremlins is never fun.

Where can I get that wiring diagram?

 

[aolshove]

Back to the flat lands, where I have access to my computer.

Firewall connectors (added MP-150 for Aux Tank):
View attachment 966664

Rear Frame connectors:
View attachment 966665

Seabiscuit68 Schematic:
View attachment 966666

Combined:
View attachment 966667

Where can I get wiring diagrams with the connector and wire labels such as you show above?

 

[DirtDonk]

Where can I get that wiring diagram?

His diagram looks like the standard one for 66 to 71 Broncos, It was typically found in the old Chilton’sn’s and Haynes manuals back in the day.
I’m not sure the currently available manuals have it, but the earlier ones did.

Can very possibly also be found on the Seabiscuit website with some great diagrams covering, if I’m not mistaken, all yours of Early Bronco.
I forget the exact address, but it’s been posted here many times and quite a few have saved it.
Hopefully, they’ll try Man to show you.

Also, search Member Steve83‘s super motors pages. He’s got very updated diagrams, but I don’t know if they cover the 70 and earlier models.

 

[aolshove]

His diagram looks like the standard one for 66 to 71 Broncos, It was typically found in the old Chilton’sn’s and Haynes manuals back in the day.
I’m not sure the currently available manuals have it, but the earlier ones did.

Can very possibly also be found on the Seabiscuit website with some great diagrams covering, if I’m not mistaken, all yours of Early Bronco.
I forget the exact address, but it’s been posted here many times and quite a few have saved it.
Hopefully, they’ll try Man to show you.

Also, search Member Steve83‘s super motors pages. He’s got very updated diagrams, but I don’t know if they cover the 70 and earlier models.

Thanks for the help. Unfortunately, the Seabiscuit68 site is gone.

 

[DirtDonk]

Noooooo! Say it ain't so!
The good news (hopefully?) is that old website pages never die. They simply get accessed through a different format. I think you type in the word "archive" first, or something like that?
I'm going to give it a try.

Paul

 

[DirtDonk]

That's funny. But most of the things that come up, are discussions here on Classic!
But they're full of images that you can access.
And, since the Bronco wiring was "basically" the same throughout the years (with differences that can easily be accounted for), you can access Steve83's diagrams and extrapolate.
But I sure did enjoy the early style of diagrams, even if they didn't quite match my '71 (even though listed as such) and I had to punt a few times.

I'm sure someone will come up with a search solution soon.

Paul

 

[dmoses42]

It might just be my computer, but I've noticed lately that when using Steve's diagrams, clicking the pic doesn't enlarge the image anymore. It used to enlarge if you clicked on the image, but it doesn't anymore for me. Like I said though, it could be something afoul on my computer. Technology hates me.

 

[chuckji]

Bronco Graveyard has a bunch of technical documents here.