The descriptions that led you to believe that was a neutral safety switch were accurate enough as far as they went, but were aimed at automatic transmissions only and have 4 wires. As you now know, this 2-wire switch is for the backup lamps. Which will be great to get back with the new harness!
There were actually some manual transmissions that had smog-equipment switches related to the "ambient system" including switches and sensors, but I think those were limited in their numbers.

FYI for it you're ever working on another Ford vehicle, some (cars and trucks) had their NSS on the lower portion of the steering column under the dash, rather than the side of the transmission. Does not effect you in this case, but for future reference.
Nothing on the old harness was connected to it. I suspect the NSS was bypassed. For me to do that, Painless made it easy. All I have to do is connect the two red/blue wires together, and go on with my life. The instructions on the proportioning valve are confusing me a little too. It came with 2x purple/wht wires. My understanding is one is power from the harness and the other goes to ground. The second wire seems to be extra. There is a connector on end, that I guess connects to something in the harness.

Someone can confirm the function of that switch, but if it's the only one on the transmission, it's for backup lamps.

Under normal circumstances, only the one. Red w/blue is your START signal wire that energizes the relay. The only other wires that are ever connected there (to my knowledge anyway) would be something needing a start-only signal for an EFI computer or some other similar function.

What colors and/or functions are they? If part of the Painless kit, they probably should not be on the "S" terminal.
And just so we're on the same page, the "S" is the small post on the left (usually) next to the larger battery side stud. The "I" connector is the small one on the starter side of the relay.

Ok the one for the ignition ballast resistor cannot go on the S post. It must go to the I post instead.
If you leave it on the S your starter will crank as soon as you turn the key to ON.

No. You're not usually getting any switched power sources from the starter relay. If you think of it simply as for starting related items only (because it is) then you'll know you have no switched power in ON/RUN and have power in START only. Won't do you any good except when the starter is cranking.
The only terminal on the starter relay that will commonly have more than one wire on it is the single large post with the battery cable to it. Those wires are for things that need constant battery power. Anything that's needing switched 12v will need to use one of the other wires that Painless provides that are switched only.

Back to the brake warning lamp switch, your original one has 2-wires and aftermarket ones have only 1-wire connectors. Your Painless kit sounds like it has two wires, so really should not be an issue. In theory one wire to each wire of the connector.
But maybe others have more insight on the brake warning lamp circuit. I'll read up on it later and add any changes I might come across.

Paul

 

Here's what I did. I went to pick and pull and found a power distribution block off of a GMC. It's a little black plastic piece with 5 or 6 bolts on it and I ran a battery sized cable to it. Thats what I use to feed all my battery hots with. main fuse panel, alternator, electric fans etc. because the lug on the solenoid is too short to put too much. They are pretty common on mid 80s trucks and suburbans.

 

Have done the same thing a time or three.
In one case I actually cut the distribution block in half (3 on one side, 2 on the other) and epoxied the exposed ends of the internal buss-bar.
This allowed me to power one group of studs right off the battery, and the other from the ignition switch so they became switched power studs.
Worked slick.

Paul

 

New information below. Moving right along....

 

Would go to the battery side of the starter relay, or the new distribution block/box you get.

Is it a larger gauge than the rest? That would be the charge wire from the standard alternator. What alternator are you going to be using again?

Yep, to the small "S" terminal.

White? Ignition module, eh? Hmm...
Painless usually uses the Ford color, which is Brown at the "I" terminal of the starter relay and feeds the ignition from the one side of the ballast resistor. I'll have to read up on the #10118 harness I guess.

Another one for the big battery side of the relay, or your new power distribution center. Wherever that ends up.

Must be switched yes. Nothing on the starter relay is switched in ON or ACC positions. The tach can be switched by just about anything, so yes the ignition side of the ballast resistor would work.
Or you could find something under the dash, such as the IVR circuit or similar. Less hassle wiring and then you only have one tach wire running through the firewall. A tach gets switched power, but also the tach signal from the ignition. Switched power can come from under the dash along with the lighting and ground circuits.

Hah! Yep, much more convenient for our electric-heavy modern world.

Does the Painless have two of the wires to match up? The point on the ignition switch is the one spade terminal on the side of the body of the switch. Away from all the other wires.
It's known in the old days as a "proof out" circuit and is grounded when the key is turned to START. In our cases, this is the test for the brake warning lamp (low brake switch) so when you turn the key to START the lamp lights up on the dash to show you it's working, then goes out when you stop cranking the engine.

Read a factory wiring diagram carefully and follow where each of the wires goes. It will work out. I would think the new switch can be used though. Check it out and look for a connector on the side of the switch. If it's not there, then I guess Painless made a mistake in switch acquisition.

Any extra switched power would work, but there definitely should be an existing one marked as backup lamps to show you the way. You probably do not need to find the power source. One of the wires is already connected at the power end and you just connect the end you see to the switch. Then the other one to the switch and then it's other end out to the lights.

Wow, that's a shock. Painless is notorious for including way too much wire in their circuits. Never ran short on any of mine I've used. Always too much and several feet of it need to be cut off before creating the terminations. Interesting...
Might be worth a call to Painless to let them know. Not sure what they could do about it at this point of course, but if it's going to be an issue for others, they should know. Unless yours is a crew-cab, long chassis cab with all custom stuff, they should be including enough wire.

Good luck.

Paul

 

I will soon be installing a similar full wire harness into a '79 F-150 4x4. Looks like the Painless and AAW systems require the change to the one-wire alternator set up. I currently have the 65 amp Ford alternator with conventional V-belt / 3 inch pulley. Can anyone tell me of a drop in one-wire alternator I could use without having to modify the mounting brackets?

 

I have a 3-wire 65 amp alternator, and all the wires were included in my Painless harness. Instructions were easy to install. Best advice I got was to remove the alternator when you wire it. Makes it much easier. Nice upgrade, but not necessary.

 

The Ford 3G goes right in. Do a search for that on here, it’s well documented on how to. I went with an aftermarket 150 amp and it pretty much dropped in also.

 

I bought a 1 wire unit from Summit for my 460 when I installed my Painless harness. Since it was for a Ford 460, there were no bracket mods needed.

 

Because the charging systems on these vehicles is so simple relatively speaking, you can use whatever alternator setup you want with whichever new harness you choose.
It's just that these companies try to "simplify" an install even more by not having to deal with any variations, and have a "just get a 1-wire and be done" attitude.

And for most intents and purposes, a 1-wire and a standard internally regulated alternator can be wired almost equally as easily.
Yes, it takes an extra wire or two to do a standard internally regulated alternator, but they're simple switched and constant power. That's it.

Basically then, just like Citymorg said, you can keep your existing setup if you choose (with either harness actually, but at least the Painless gives you new parts so you don't have to re-use your old regulator harness), or, like the others said, there are many different modern alternators out there that will work too.
I'm not a total purist, but if I can source a Ford part for a Ford, I'd rather do that than convert it to a GM or Chrysler part. Don't have an issue with the other brands, but when possible I like to keep things consistent. If only to make it easier for others to figure out what was swapped.

My first choice of swaps for the older setups, if you like external regulators (some of us do) is to use a large-case 1G Ford alternator. Simply a larger and more powerful version of what you have now.
Next on the list is a 3G swap. More power out of a small-ish body, easy bolt on to your existing brackets (most of the time), reliable with good power output at idle (this is a key parameter I feel) and easy to find.
Next would be a "1-wire" 3G (we sell that type) but only if you really, really just want to connect one wire to the vehicle. Not high on my priority list because I still feel even the 4-wire ones are easy-peasy.
Last on the list is the common "GM 1-wire" conversion. Most vendors don't call it a GM alternator. They simply say "1-wire, will fit your Ford" and leave it at that.

I'm probably leaning on old experiences rather than current results though. The old GM 1-wire units of the '70's weren't exactly pillars of the community when it came to reliability or low-rpm performance. And I don't care for the whole self-exciting feature because some of them used to need quite a bit of rpm to start charging initially. Not a big issue with modern versions I don't think. Our own 1-wire 3G conversions kick in at about 1200 rpm and have really good, typical 3G performance at idle. So I'm probably complaining about nothing, but I still like hooking up the additional wires.
An advantage of the GM 1-wire conversions is that they're relatively small-ish from what I've seen. But for me, bigger has always worked out to be better. Bigger cases would seem to dissipate heat better. And if they fit a larger, more robust set of bearings, that's a good thing too.
Don't know if either of those hold true in detail, but all of my larger bodied alternators lasted a really long time. I used to buy decent quality small alternators about every two years when the bearings would start to go. After installing the large-case alternators, I never had to buy a new one again for that vehicle!

Anyway, that's a long way of saying you can use whatever you want. Just takes a little more wiring on one, a little bit of adjustment for the other.
Most standard Ford alternator brackets will fit most conversion alternators because, unlike most parts, the mounting schemes were very similar across brands and years.
The exceptions are the heavy cast brackets, some of which also hold an air pump. If you have the simple stamped steel ones, you're probably good. If you're not sure, post up some pics and I'm sure someone can figure out if you've got usable brackets.

Paul

 

I noticed yours is a 400, but when I added a 3G to my 300 I had to notch the bottom of the bracket some so I could lift the alt. to tighten the belts. I have also gone with slightly shorter belts.

No smog pump on mine.

 

I elongated the adjusting slot on mine too. Could have gone with a shorter belt as well, but wanted to use what I had and only needed about another 1/4" of slot. Quicker to open it up than drive to the store for another belt.

Paul

 

UPDATE:

-Back-up Switch-Found the blk and blk/ylw to connect to the back-up switch on my transmission. My parking brake was not working, so I took the screws out to diagnose it (need some PB Blaster to free it up, so the ratchet would catch). They were hiding behind it in the dark. I bought a new pigtail, and will connect them, and bypass the neutral safety by splicing the red/blu's together.

-Proportioning Valve-I am just going to run longer wires, and connect per the manual--one to the instrument cluster and one to the ignition switch. Which brings me to a question about the ignition switch. The new switch that came with the kit has 6 posts to attach 4 wires, one of which is a neutral safety. How confident can I be that if I connect to one of the empty posts that it will be switched when the engine is on? How likely would these posts only be hot when in ACC or START? How can I tell besides putting a multi-meter on it when everything is back together? I actually bought two power distribution blocks. One is 4ga in and 4 out of varying ga. The other is a simple 1 in-10 out. I am planning on going from the battery to the first block with a 4ga wire. I will probably come off the S side of starter solenoid, just because of the small post. Then send out to the heavy-duty headlights and amplifier, as directed. Do these draw power when connected directly to the battery when they are not turned on? If so, I would rather connect them to the other block. The other block I plan on connecting to red/grn that is going from the fuse block to the pos. side of the ballast resistor. From what I can tell, this should be switched. If so, I will connect the pos. to my voltmeter, tachometer, wire from ignition coil, dashcam, and anything else that needs to be switched. Even better would be if I could connect it directly to one of the empty posts on the ignition switch (see above.)

-Taillights--Was able to run the wires, one at a time, without dropping the gas tank (Yeah!). Going to start connecting, and include a trailer harness. Should be straight forward and easy.

-Instrument panel--This is the part that looks complicated. Instructions say to reuse the existing plug for the panel, and run new wires to it. New wires do not match the colors of the old wires, but there is a pretty good diagram in the instructions. Says I can use a flat head to pop out the old wires, solder the ends onto the new wire and plug it back in. I think I am just going to cut and use butt connectors. It is a really old plug, and I don't want to break the plastic. Any advice on connecting the wires?, this looks like the hardest part, especially since the '78 might be a little different from the '77.

--Headlight switch--Just like the ignition switch, the new headlight switch seems to have empty posts. I am adding 4 after market gauges (temp., oil pressure, volt., and tach.) I would like to connect the lights so they come on when I turn the headlights on. Can I connect this to one of the empty posts?, or do I need to splice into a labelled headlight wire?

Thank you all so much for answering all of my questions, and helping with this project. I am planning on posting some how to information when I get done.

P.S.-sorry to disappoint, I soldered as much as I could with the harness on the table before I put it in. Once I got it into the truck, there were just too many connections. Since I was outside, I had limited access to power. I chose to use connectors with heat-shrink connected to them instead.

 

Take a look at this to help build a better system. It has helped me a bunch. Im rewiring my 77 right now. I'll take pictures tomorrow and post them up for you, I used a wiring block which you will see in the pictures.


Here is the link read up great info . Improved Power Circuit!

 

ok here are a couple of pictures , im engine is dirty because i crushed my arm back in nov and never got to stick the hood back on.

i still need to wire in the 220 amp fuse block here