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Power Distribution Redo

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BabeTheBlueOx

Power Distribution Redo

Hi All,

The wiring on my bullnose is a mess. Someone was in it at one point and left a rat's nest of wires and inline fuses. Whenever something quits working I chase down bad grounds, wire breaks, fuses in odd places, basically all the "stuff".

I was reading about relocating the fuse block in Gary's writeup, and am wondering what size lift it would be to locate a fuse block in the engine bay and rewire one circuit at a time into the new circuit block. Just bypass the existing wiring a little bit at a time until it's all gone.

It can't be too complex on a carbureted engine, right? Lights, ignition, distributor, wipers, alternator, radio, a few dash indicators, etc.. etc..

It seems like it will be a lot less work than trying to trace and patch together the existing circuits.

Thoughts and experience?

1985 F350 4x4

81-F150-Explorer

Re: Power Distribution Redo

It depends on your skill level.

I've done complete re-wires of vehicles. I find it easier to take an existing wiring harness, take it out of the vehicle, unwrap it, and repair one circuit or wire at a time on my table.

With the right connectors, terminals, plugs, and tools you can repair an existing harness to like new condition.

I had a busted/broken fuse panel as example, and all it took was 30 minutes of transferring the wire terminals from the broken one to the new one, and putting the fuses back in place.

What I would do if this was my project. I would get a reputable wiring diagram for your truck, remove the problem harnesses completely from the vehicle, un wrap the harness, and get rid of all the aftermarket stuff attached. Then I would test each color wire individually with a multimeter set to ohms, and then repair each wire that had a problem. Once the wiring was fixed to factory specs, then I would add back the extra circuits you need or require, the proper way.

For me, redoing a whole new Power distribution system would be a lot harder for me to do than repairing and fixing the old one.

But each person is different.

P.S. Whatever way you chose, I would not recommend replacing just one circuit at a time, knowing there are other issues with other circuits. One section of harness at a time, yes, but one circuit at a time could cause unforeseen issues, and some that could be dangerous.

Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.

Gary Lewis

Re: Power Distribution Redo

Administrator

In reply to this post by BabeTheBlueOx

That's an interesting question. And you will probably get several very different answers. In fact, you might get more than one answer from me.

First, what you linked to is what I have planned to do for Dad's truck, but haven't done it yet. However, I've done that an more on Big Blue.

I used an identical power distribution box on Big Blue's passenger's side and put the circuits shown in it. However, it turned out that the Bosch cube relay is not strong enough to pull in the PMGR starter that I have and started giving problems. So I rewired and went back to the standard fender-mounted relay for the starter. But I kept the fuses replacing the fuse links.

Later I converted to EFI and put a similar power distribution box on the driver's side of Big Blue, and it has things like the fuel pump relay, EEC relay, etc in it.

And now to your question. I guess it depends on where the problems are with your wiring. If the issues are downstream of the fuse box then I don't think changing would help. So, where are the problems?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ratdude747

Re: Power Distribution Redo

In reply to this post by 81-F150-Explorer

If you have a bunch of new circuits with inline fuses, I suggest installing an auxillary fuse panel. Which I recently did to mine and documented here:

https://forum.garysgaragemahal.com/Electrical-distribution-and-lighting-upgrades-tp127722p129831.html

$17 on eBay, included some fuses too.

Now in my case, I had already upgraded to a PMGR starter which allowed me to move non-starter battery power distribution from the starter relay to the new fuse panel. If using the moving pole starter (and no plans to upgrade to PMGR), one could replicate this by moving everything but the battery feed to the starter relay; one would branch from the relay to the fuse panel, and everything else to the panel.

Is it as fancy as some of the other builds around here? No. But it works and wasn't too much extra wiring.

1984 F150: 300 L6, AOD, RWD. EEC IV / TFI, Feedback Carter YFA Carb. Stock everything but radio (for now).

BabeTheBlueOx

Re: Power Distribution Redo

In reply to this post by Gary Lewis

Great advice all around so far, thank you all so much.

81-F150-Explorer wrote

What I would do if this was my project. I would get a reputable wiring diagram for your truck, remove the problem harnesses completely from the vehicle, un wrap the harness, and get rid of all the aftermarket stuff attached.

I'm very comfortable with electronics and wiring. Your "remove one wiring harness at a time" strikes a note. That would be a very controlled approach to getting everything back to standard wiring and quality. Can you point to any resources that go through wiring harness removal? I'm guessing it's probably pick a starting point, then disconnect and follow until you get an entire harness off, but I've been WAY wrong before.

Gary Lewis wrote

And now to your question. I guess it depends on where the problems are with your wiring. If the issues are downstream of the fuse box then I don't think changing would help. So, where are the problems?

The problems have all been downstream so far with wire breaks and bad grounds. But the fuse block under the dash has cut wires hanging off it, wires pressed into fuses from the top, wires spliced together with electrical tape.. everything you can imagine. So I'm kind of looking at this as a "fix it before it breaks" project so I can pick convenient times to have the truck out of service.

1985 F350 4x4

81-F150-Explorer

Re: Power Distribution Redo

BabeTheBlueOx wrote

Great advice all around so far, thank you all so much.

81-F150-Explorer wrote

What I would do if this was my project. I would get a reputable wiring diagram for your truck, remove the problem harnesses completely from the vehicle, un wrap the harness, and get rid of all the aftermarket stuff attached.

I'm very comfortable with electronics and wiring. Your "remove one wiring harness at a time" strikes a note. That would be a very controlled approach to getting everything back to standard wiring and quality. Can you point to any resources that go through wiring harness removal? I'm guessing it's probably pick a starting point, then disconnect and follow until you get an entire harness off, but I've been WAY wrong before.

No that is pretty much it. Each section has it's own harness, like the Alternator Harness, left and right engine bay harness, frame-rail harness, taillight harness, and things like that. They all unplug in full sections for easier service.

Even the main harness under the dash is removable, just time consuming etc. Removing the dash pad can give good access, after the A/C ducts are removed for example, if even equipped with A/C.

So pick the most screwed up harness, and go from there, and work forwards/backwards etc.

As for resources, this site is a really good one for help. Look at the top under documentation, then electrical for some good information. If you have questions, ask here and one of us will be able to help. Pictures also help us understand what is going on if you have a problem.

Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.

BabeTheBlueOx

Re: Power Distribution Redo

One more question (until the next one).

Do you have a recommended approach/parts to replace the connectors between harnesses if they need replacement?

1985 F350 4x4

BabeTheBlueOx

Re: Power Distribution Redo

I answered my own question after some for searching:

https://www.garysgaragemahal.com/#nabble-td23210

1985 F350 4x4

Gary Lewis

Re: Power Distribution Redo

Administrator

Sorry that I missed your question, but you found a good thread on that subject.

Gary, AKA "Gary fellow": Profile

81-F150-Explorer

Re: Power Distribution Redo

I'm sorry as well. Hope things are going well.

Yes, used harnesses are a great place to look for connectors. Ford cars from the same era can produce connectors that you can use as well.

Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.

BabeTheBlueOx

Re: Power Distribution Redo

81-F150-Explorer wrote

Yes, used harnesses are a great place to look for connectors. Ford cars from the same era can produce connectors that you can use as well.

I'm into the harness-pulling-and-checking project, it's going really well. I've got a big mess on my hands but it's been educational to pull everything apart, clean it, fix it, and put it back together. It's much less complicated than I thought.

I've got some moulded connectors that have wire breaks so close to the moulded base that soldering it back together is going to be a very fragile fix. My gut tells me that replacing the connector on both sides with something new/modern is going to be far less effort than junkyard diving for a replacement.

Any experience with that? Any gotchas that I'm not thinking through that could bite me?

1985 F350 4x4

Gary Lewis

Re: Power Distribution Redo

Administrator

That question may have been to Ralph, but I'll jump in anyway. Yes, there have been plenty of times I really couldn't salvage a connector. Ford sells some of them via their catalog shown on our page at Documentation/Electrical/Connectors. Or you can go modern and get new connectors like Rusty is doing here. And Amazon sells kits, but watch out that you aren't expecting them to carry a lot of current as most of those are limited to 10 or 12 amps.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: Power Distribution Redo

Administrator

In reply to this post by BabeTheBlueOx

I found a source for the DS-II connectors, but many of the others, not as easy. Ford went through several iterations of weatherproofing connectors. Early attempts were to simply fill the connector with a type of grease, which, unfortunately hardens with age and dries out. Next were the molded plug/socket pairs again with a grease to exclude water. I updated all the harnesses on my 1986 F350 to the 90s style, sealed outside connectors that use O-rings or gaskets and rubber plugs with only the needed holes for wires.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

BabeTheBlueOx

Re: Power Distribution Redo

Thanks Gary and Bill, that makes me feel more confident about replacing connectors.

After pulling apart the first taped-together-ratsnest-of-wires, I was happy to see that it wasn't as complicated as I thought. Just like untangling a bunch of fishing line.

I put it all back together, crossed my fingers, and fired her up without any issues. I'm going to order some new connectors and some split wire conduit to do a final cleanup and routing of all the harnesses when we swap the engine out this spring.

1985 F350 4x4

Gary Lewis

Re: Power Distribution Redo

Administrator

Well done!

Gary, AKA "Gary fellow": Profile

81-F150-Explorer

Re: Power Distribution Redo

Glad that you got it up and working.

Yes, I agree with Gary and Bill.

It's best to try and get the Ford connectors for parts compatibility, but sometimes new is the only way possible. Just make sure that the new connectors is rated for the same amp/voltage as the old one.

In the connectors used for our trucks, Ford used White Lithium Grease in the connectors. I bought a pint of it in 1992 and I am still using that same pint.

When the connectors get dry, just put more into them.

Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.