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So I finally did it and so very happy I did. Found a 79 donor at you pull it and stole its under dash, frame, and rear 1/4 wiring harnesses to replace my 78's damaged/burned up harnesses that have been a hassle for almost 20 years. Its been a fire hazard for too long.

The 79 harness had A/C and Cruise Control but I found that they just put this in the harness between the column connector and dash connector. I simply removed it and the brake portion of the cruise control harness and had the proper wire and connectors for my plain Jane 78.

A couple of pictures, sorry, my camera sucks and its on my wants list.

Factory melted/fried harness pieces, notice the dead end wires, jumpers etc. NIGHTMARE:





The entire harness was similar in condition to those connection points ^.

New harness:
I stole the radio wire and fuse holder from my 78 and re wired it into the new 79' harness. I also had to remove a damaged cigarette lighter wire and run a new one but I landed them properly at the fuse box and harness ends.

I un wrapped, re wired and re wrapped the harness, the zip ties are just holding things in place until I got it wrapped up.



You can see the factory radio wiring (Yellow), I stole this from my 78' and inserted to the 79' so I could have the entire harness 100% factory (minus the door switches). You can also make out the newer green wire to replace the damaged cigarette lighter wiring. Splices are soldered and heat shrink-ed:



I plugged it all in including the gate wiring (minus the front to rear harness that has damage) and BAM, everything worked first try! Well, almost everything. I found a dirty corroded hot lead on the new harness where it meets the blower motor. Cleaned her up and presto, everything is 100%.

I'm doing the front to rear harness this week, only one splice point for the sending unit. At that point everything except the headlight pigtails and a few shorties in the engine bay will be 100%.
 

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Sounds like a fair bit of work. I really wish somebody would actually make the complete Bronco harness available for sale. JBG has long had a placeholder in their catalog, but still nothing more than that. I want a new one, not another 33-year old harness but I'm too spastic to completely re-wire it myself. By the time I got done, I'd have to use the tailgate window switch to start it and push the cigarette lighter in to run the windshield wipers. :toothless


So how well has it worked for you now that it's been a few days?
 

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Discussion Starter #3
....... By the time I got done, I'd have to use the tailgate window switch to start it and push the cigarette lighter in to run the windshield wipers. :toothless


So how well has it worked for you now that it's been a few days?
Oh it was a bit of work alright but really worth it. I was able to get the front-to-rear harness (Frame) in on Monday night along with the little pig tail up into the left rear tail light assembly. Last night I disassembled my column and installed the new signal switch and harness (After market) and replaced the bulb for the shift indicator.

I couldn't be much happier with the results. I did however get lucky to find a decent harness, one that survived the majority of hacks and stereo installs.

You mentioned that it might be confusing and things getting mixed up. I wouldn't worry about that too much. Ford made these things pretty idiot proof. For instance you can't get a plug to snap together unless its supposed to. Every plug (For the most part) is a different shape and or color, you wont screw that up.

The hardest part is the little stuff. I had to steal the old stereo wire and fuse holder for the radio and another for the courtesy lights. I re- used them with the new harness because those items were damaged on the new harness. I also had quite a bit of work sorting things out prior to the install. I think my advice to anyone attempting this would be to gut the entire dash and tag things as you unplug them if you are not confident with wiring. Place the dash harness in your driveway next to the new one and identify things and tag them to the new harness. It doesn't hurt to snap a picture now and then either and take your time before you unplug things, try to understand what the wire/switch/device is for and then its pretty simple from there.

I think the only real frustrating part was the pig tail harness for the tailgate wiring behind the left tail light assembly. Only because I just got all that working perfectly with old damaged wires before the harness swap. I made the swap and no workie. I futzed around with it for a while and found that the new jack with perfect wire was dirty as hell. The electromotive cleaner I used (NAPA) SUCKED. It leaves a film of powder on everything. Another NAPA crap product. I cleaned it up and it works fine. Sorry about my Napa turrets syndrome but lately they are pi pi pissing me off!

Make sure you find a clean harness before you waste your time doing this. The donor was in really good shape minus the wires I mentioned above, the hacked trailer wires (Fixed), and the lose/missing fabric wrap on the wiring. All easily fixable with some patience. I need to crawl back under and wrap a few areas once I replace my neutral safety/back up switch. Right now everything including my trailer lights work minus the back up lights (Switch) and license plate lights which are next as is some new door switches. Every damn dash light/courtesy light, marker, signal, brake etc etc etc works perfectly. Even the goofy cash tray light works as well as the peep hole light in the glove box.

If you want to keep it real clean and if you can solder, most of the jacks come apart. You can get the actual spade connector out and solder a new wire on it, then snap the spade back into the actual connector. It makes for a nice factory connection that serviceable.


I think I did it all for 55 bucks for the harness from U-Pull-It-Out-In-The-Rain-Under-The-Bronco-In-The-Mud plus another 67 (Including S&H) for a Rock Auto Turn Signal switch. Oh yeah, the new re-po signal switch worked perfectly except for the fact it didn't have the blue/wht wire and bulb socket for the shift indicator. Easily fixed if you take a part the multi-pin connector. I stole the original pin,wire, and bulb socket from the old signal harness and installed it into the new connector/harness and presto.

Oh yeah, Rock Auto= :rockon
 

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what's wrong with a universal wiring kit and new plugs?

It's not that hard, just take your time doing it.
 

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Discussion Starter #6
what's wrong with a universal wiring kit and new plugs?

It's not that hard, just take your time doing it.
I don't think there's anything wrong with it, except for the price. I can't afford the universal harness that I wanted so I went to the You Pull It and spent 55 bones on the three pieces I used, a mint door panel, some aluminum trim parts, wiper knob, and a rear seat striker /bucket assembly. That and I prefer factory when it comes to that sort of thing.
I used to work in a custom shop, I do like some of the aftermarket harnesses that we worked with but again, I think they are over priced for what you get and for what I want to do.
 

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I don't think there's anything wrong with it, except for the price. I can't afford the universal harness that I wanted so I went to the You Pull It and spent 55 bones on the three pieces I used, a mint door panel, some aluminum trim parts, wiper knob, and a rear seat striker /bucket assembly. That and I prefer factory when it comes to that sort of thing.
I used to work in a custom shop, I do like some of the aftermarket harnesses that we worked with but again, I think they are over priced for what you get and for what I want to do.
My post was more to the folks complaining about no new harness available.


I pulled mine out and rebuilt it pretty much. Luckily mine wasn't too butchered and it required a few repairs.
 

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Discussion Starter #8
My post was more to the folks complaining about no new harness available.


I pulled mine out and rebuilt it pretty much. Luckily mine wasn't too butchered and it required a few repairs.
I understand. That's a little why I posted my swap as well, there's always a way.
I recommend a documentary to anyone that loves to work on cars, its called "Yank Tanks". Takes place in Cuba and if they can keep that old rusty crap running down there then there is no excuse for those of us that have access to parts yards.
 

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Well, the plans you laid out make sense and I appreciate all the "gotchas" - but I'm not taking this on alone. I'll make sure I have somebody who actually understands this stuff to help me out before I start yanking wires & connectors.

Related note: My dad had to swap the leads on his '51 Ford F4 the other day because his ammeter was reading negative... turns out the truck is factory wired as a positive ground & the PO wired the battery as a negative ground. Took him 5 minutes to make me understand WTF that meant... so there's a clue as to how electrically intelligent I am.
 

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Well, the plans you laid out make sense and I appreciate all the "gotchas" - but I'm not taking this on alone. I'll make sure I have somebody who actually understands this stuff to help me out before I start yanking wires & connectors.

Related note: My dad had to swap the leads on his '51 Ford F4 the other day because his ammeter was reading negative... turns out the truck is factory wired as a positive ground & the PO wired the battery as a negative ground. Took him 5 minutes to make me understand WTF that meant... so there's a clue as to how electrically intelligent I am.
Usually when your ammeter reads negative, it's because you have the ammeter leads swapped, not the vehicle leads. For example positive ammeter lead to negative cable. I though the electron theory proved that electrons travel from postive to negative? Someone correct me if I'm wrong?
 

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Related note: My dad had to swap the leads on his '51 Ford F4 the other day
because his ammeter was reading negative... turns out the truck is factory
wired as a positive ground & the PO wired the battery as a negative ground.
Took him 5 minutes to make me understand WTF that meant... so there's a
clue as to how electrically intelligent I am.
That's a start, just don't stop learning it, that's all. :)

When I was a kid I remember seeing a guy in a
wheelchair with cerebral palsy that was an M.D.

So don't give me this "i caynt" crap. ;)
You can do it, just friggin' apply yourself.

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I agree that Ford used minimum wire size! :/
(well known fact) ...but it -does-work-. ;)

Can't a wrecking yard harness be fixed-up cheaper and
easier than starting from scratch tho? The OP did it. ;)

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My '75 F150 with a jillion ;) high speed dirt road miles
has had two sockets get rusty and one where a wire
broke loose right at the socket.

When I had the bed off noticed a few places where the
insulation had almost worn through to the wire. I just
taped the whole stretch back up and re-bent the wires
so they'd wear in new spots. LOL :)

YMMV on all that. ;)

Alvin in AZ
 

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I though the electron theory proved that electrons travel from
positive to negative? Someone correct me if I'm wrong?
If electrons are negatively charged, does it make sense that they'd be
attracted to the negative side? ;)

Back from when I was a kid I remember people having lots of trouble
with hooking batteries up backwards and burning up stuff because
there were both positive and negative grounded vehicles around.

And there were old-fart auto repair shops everywhere specializing in
certain parts like radiators or transmissions or electrical etc. You can
still see that separation in Mexico. :)

Alvin in AZ
 

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That's a start, just don't stop learning it, that's all. :)

When I was a kid I remember seeing a guy in a
wheelchair with cerebral palsy that was an M.D.

So don't give me this "i caynt" crap. ;)
You can do it, just friggin' apply yourself.
Hey I didn't say I can't... I said I WON'T. Just 'cause I can doesn't mean I should. :histerica

My '75 F150 with a jillion ;) high speed dirt road miles
has had two sockets get rusty and one where a wire
broke loose right at the socket.

When I had the bed off noticed a few places where the
insulation had almost worn through to the wire. I just
taped the whole stretch back up and re-bent the wires
so they'd wear in new spots. LOL :)
That's the sort of thing I'd like to avoid with a NEW harness. The point isn't the cash - it's the long-term renewal. I can grab another 33-year old harness and put lipstick on the pig... but I'd sure like to "restart the clock" and have that last another 33 years. Make sense?
 

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Hey I didn't say I can't... I said I WON'T.
Just 'cause I can doesn't mean I should.
It was meant to -keep- you from saying "i caynt".
I didn't expect you to go backwards. ;)

That's the sort of thing I'd like to avoid with a NEW harness. The point isn't the
cash - it's the long-term renewal. I can grab another 33-year old harness and
put lipstick on the pig... but I'd sure like to "restart the clock" and have that last
another 33 years. Make sense?
Nope. :)

There's railroad signal wiring and electrical mechanisms on the old SP that
are still in service since from well before 1925 and there's no good reason
to change any of it out until an equipment change is called for.

There are lot older Fords than yours running good with their original wires
and other electrical parts in 'em. My '75 F150 for one. Check out all the
old 60's style Ford pickups around still.

Do what you want, just don't piss down my back and tell me it's raining. ;)

Alvin in AZ
 

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I'm going through the same thing now, but building my own harness. I just bought new connectors and have been running all the new wiring and bundling them up. It takes forever, but I know it will last a good while. I wasn't able to find any good donor harnesses that's a pretty good find for a 30+ year old truck!
 

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I'm going through the same thing now, but building my own harness.
I just bought new connectors and have been running all the new wiring
and bundling them up. It takes forever, but I know it will last a good while.
I wasn't able to find any good donor harnesses that's a pretty good find
for a 30+ year old truck!
That's cool. :)

If you can't find one you can't find one. :)
I got one from my '75 parts truck. ;)

My son is thinking he'd like to just run his own wires but not re-do the
whole stinkin' truck, just half the stuff under the dash making wiring
changes he'd like as he goes.

Just don't tell me "i caynt", please. LOL :)

Alvin in AZ
 

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Man these old trucks have rats nest for wiring. I tackled a wiring fix when i was 16 in my old 78 f250. Took forever but ended up getting it all fixed nicely. For being 30+ yrs old, they still had several dang wires in them
 

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Discussion Starter #19
I added one more new piece of wiring, the neutral safety switch. Needed my back up lights to work since everything else works (minus the license plate lights and burned out cig lighter).
K, I'm a low voltage electrician, mostly Audio Video integration, Data/com, etc etc. The damn left rear reverse light just kicked my ass for 45 minutes. My test light showed good but the bulb wouldn't light. I'd jumper a ground to the bulb while in the socket and it would work. I found a crusty connection inside the socket itself, it had enough power for my test light but not the 1156 bulb :banghead
I know better too, that's why there is a volt meter just 3 feet from where I was working LMAO.
 
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