Wiring Harness Suggestions

[zimzimma]

I have read lots of wiring harness threads but I think my case is somewhat unique so I am looking for suggestions. And I am one of those people who is on a tight budget. I have the RJM EFI Harness, upgraded headlight harness (relays, etc), Explorer serpentine setup with new 4G alternator, BC Broncos EFI tank, PMGR starter and a few other wiring updates. All large gauge cables around the battery and alternator have been redone and are in good shape. I don't have any questionable butt connectors or wire splices. If a wire has looked in bad shape I have replaced it. My behind the dash wiring is original 1977 (aside from the current loop wire which has been disabled). The fuse box is original 1977. It has original wiring going back to the taillights although at some point I changed out the connectors to weatherpack for some reason. The wires from the headlight switch to the updated headlight relays and turn signal wires are original. I don't currently have any issues. Things tend to work, but every once and a while I see a thread about a wiring harness fire and I get worried. All the Bronco specific harnesses sound like I will be cutting up and throwing out half of it (including half of the money spent on it) because of my modifications. But I like the idea of keeping the fuse box in the glove compartment. Right now the Bronco is not even registered. Its more of a 30 year ongoing project (remember when you could get a decent one for $500?). But I just purchased new tires and would like to register soon. It will be all street use and long trips are unlikely. There is no place to go offroad near me. I will not be installing a winch or any extra high draw consumers.

Any suggestions of what might make the most sense? I would prefer some sort of kit, even if its universal. I don't have the time to make my own wiring harness from scratch even though that might make the most sense given my situation. Or maybe I should keep what I have until something breaks? I just don't want to end up with a fire from a 45 year old wire.

Thanks

 

[bigmuddy]

Personally, If your confident in your wiring skills I would run it and stop worrying and get it on the road, Enjoy during good weather and rewire if you have the time and money over the winter (assuming you have cold winters)

With regard to harness's aftermarket I prefer the old centech, in particular if you have upgraded a bunch of wiring anyway. Centech has limited fuse capability (like stock) but I have added a painless ext harness and been happy.
I had zero issues with both my Centech installs.

I recently started to install the fancy Painless harness and frankly was disappointed as I too had an issue with wiring that was wrong in the harness and or didn't copy with what was in their included schematics, which for a relative laymen is a tremendous problem. Apparently and from what I was told from a bronco builder that builds 6-7 broncos a year and it's common. He suggested autowire harness's FYI.

Best of luck

 

[toddz69]

I'd echo @bigmuddy's sentiments. It sounds like you've maintained your harness well with all the add-ons/updates, etc. Presuming all your mods were done well, and we'll assume they were , then just run it as-is.

Todd Z.

 

[joebronco73]

Personally, If your confident in your wiring skills I would run it and stop worrying and get it on the road, Enjoy during good weather and rewire if you have the time and money over the winter (assuming you have cold winters)

With regard to harness's aftermarket I prefer the old centech, in particular if you have upgraded a bunch of wiring anyway. Centech has limited fuse capability (like stock) but I have added a painless ext harness and been happy.
I had zero issues with both my Centech installs.

I recently started to install the fancy Painless harness and frankly was disappointed as I too had an issue with wiring that was wrong in the harness and or didn't copy with what was in their included schematics, which for a relative laymen is a tremendous problem. Apparently and from what I was told from a bronco builder that builds 6-7 broncos a year and it's common. He suggested autowire harness's FYI.

Best of luck

I understand that Centech is no longer being produced, though, I agree: if OP trusts his own ability to fix wiring, it's better than spending the big bucks for a kit.

I'm starting my Painless kit as well. Is the problem a matter of wire color/labeling or something more severe like full lengths of wire missing?

 

[DirtDonk]

Where have you read about fires? Broncos have been one of the least problematic in that regard. All the fires I know of were from poor quality, hack job modifications, overpowering the existing battery charge wire with a big alternator, letting the connections get corroded at the ammeter or on the ‘70 and earlier models where the firewall pass-throughs were a problem. Or bypassing a fuse. OR… removing a fusible link meant to prevent fires!
Not really a big issue on 71 and later Broncos, since they don’t have the two big firewall connections.
Again, unless something was hacked.

Is rust a problem in your area? Is your bronco suffering from it on the sheet metal? If so, then wire connections get corroded. If yours look good, then that should not be an issue.
There’s one bit of general maintenance that you can do, however, and that is pull all the fuses out of the fuse block, wipe them off, make sure the contacts are clean in the block itself, and reinsert them.
Every year or two you can repeat this because a layer of oxidation builds up on the metal parts and impedes the flow of electricity.

Did you connect your new PMGR starter through the old starter relay on the fender? If not, I would reconsider using that. Takes a lot of the load of the new starter off of the ignition switch.

Have you upgraded your grounding protocols? Broncos came with minimal major grounding, so can benefit from some additions. We’ve discussed them here many times, but would be happy to run them down again if you need.

You’ve got all the major upgrades, so there really doesn’t sound like there’s any problem.
The original headlight wiring is under so little strain now with the relay set up, that there’s almost no load on them.
The new heavy charge cable from the alternator completely bypasses the original charge loop. So very little load on the old wire. The only load it sees anymore, is whatever is being used in the cabin and through the fuse panel.

What exactly do you mean by you disabled it?

Normally that only includes not reconnecting it to the new alternator. Doesn’t mean anything about disconnecting it under the dash, in case that’s what you did.

There is absolutely zero danger of the ammeter causing a fire in a Bronco, because it was a special type. Only if the main connector got loose or corroded and overheated. But if yours has been apart, inspected and sealed, you’d be in good shape. Especially now, that you don’t have any real current flowing through it except what’s being used by the accessories.
Did you get rid of your ammeter and replace it with a voltmeter?
Have you looked up behind the dash at the back of the fuse panel in the glove box to see that it’s not corroded or has any other deteriorating connections? Th
If all that’s good, then so are you.

One remaining thing that might cause you to change all the harness. Are your original wires getting hard and brittle?
A friends 77 was, so we replaced his harness. Wasn’t worth the trouble of waiting for trouble to find us.

So obviously, I’m with the others and recommending you just get it on the road. As long as you have fuse protection in the main charge wire from the alternator, retain your fusible link or add a fuse to the main power wire at the starter relay to the cabin, and have all your other fuses in good condition, you should be good to go.

 

[bigmuddy]

I understand that Centech is no longer being produced, though, I agree: if OP trusts his own ability to fix wiring, it's better than spending the big bucks for a kit.

I'm starting my Painless kit as well. Is the problem a matter of wire color/labeling or something more severe like full lengths of wire missing?

Damn I hate to hear that.
Mine specifically was miss-wired at the wiper switch and was also miss labeled on the wiring schematic. couple of other issues with wire colors not matching the schematic as well. I suspect they either ran short on the correct color and swapped with regard to changing/printing new diagrams but still as much as you pay for a "quality" kit it should be accurate. Nothing like chasing wiring issues..

 

[joebronco73]

Damn I hate to hear that.
Mine specifically was miss-wired at the wiper switch and was also miss labeled on the wiring schematic. couple of other issues with wire colors not matching the schematic as well. I suspect they either ran short on the correct color and swapped with regard to changing/printing new diagrams but still as much as you pay for a "quality" kit it should be accurate. Nothing like chasing wiring issues..

I'll keep this in mind as I start installing my harness. If I come across it, I'll be sure to update the forum about it.

 

[bigmuddy]

Yeah, just got over every wire connection then recheck the colors and connections before installation.

I had smart cookies that helped me and so they were running continuity and checking power over the whole harness before installation.

 

[DirtDonk]

Sorry to hear about both Centech stopping Bronco harness production, AND problems with the Painless.
In the original harness from Painless, the only thing I remember being the wrong color was the main ACC wire from the back of the ignition switch. This was pointed out to them very early on, but it was one of the few things they seemed unwilling to make the change on. Would have been easy right up front before it got into main production, but oh well.
The original Ford wire is Black w/green stripe. I forget what the Painless color is (Yellow maybe?) but at least it's marked/lettered correctly. Or at least it was...

Is there a discussion hereabouts where the incorrect wire colors and/or markings and/or locations are discussed?
As far as locations are concerned, they have always maintained they deliver theirs with simple wire ties capturing the bundles, so any re-locating of wiring can be made before, or even during the installation.

Now I'm going to have to go back and look at mine. It's relatively new-ish anyway (maybe less than a year?) so might have the issues mentioned. I did not notice any when I gave it a cursory inspection, but I wasn't looking for that type of issue at the time either.

Paul

 

[zimzimma]

Thanks all,

That's kind of what I figured. Now I need to come up with another excuse not to register it and put it on the road.

To answer Paul's questions; the only places I have heard of fires are on here. I understand it isn't common and you are right, they are probably hack jobs where it happens.
I'm in Connecticut so we certainly get our fair share of corrosion.
I have the PMGR running through an early 90's Ford starter relay. The black with yellow tracer wire that was for the current loop is disconnected and heat shrunk over by the wheel well. No issues of running through too much current as there is no current running through it at all. I don't remember what I did with the other end of the wire. It has been too long. I should probably check it and refresh my memory. The ammeter is just there doing nothing. I know enough to ignore it. No voltmeter - I should plan on that along with a tach. I have extra grounds all over - but still probably not enough. Very heavy new cable grounding the alternator to the engine and to the battery and another big cable between the engine and body. And the usual smaller grounds as necessary.

Main charging wire has a megafuse, EFI stuff and the headlight relays have regular blade fuses. But the original wiring is on the brittle side behind the dashboard and where it is still running throughout the Bronco

Good suggestion about pulling the fuses. That is something I should do.

-Matt

 

[DirtDonk]

Some important things you need to know about the black wire that is the charge loop.
You still need most of it.
1. The end that is at the starter relay’s battery side must remain. Without it no power gets to the vehicle. Period.
2. The connector at the animator must remain connected. Without it, you get no power anywhere in the vehicle.
3. Only the end that was originally connected to the alternator needs to be covered and protected from shorting out.
Or, the best way to utilize its capacity is to create a power stud where you can connect other wires to power other accessories you might add later.
Not necessary if you never plan to add anything electrical. But handy to have if you do.

So when you’re tracing all these wires, look at both ends of that black wire. The black with yellow stripe section was usually the alternator end, while the end at the starter relay was typically all black. A 77 might’ve been black with a red stripe.
With your current setup, your alternator charges the battery directly, but does not power the vehicle. Your original black wire will take care of that.