Another issue is trying to use an idiot light wiring harness with a gauge cluster. Doesn't work.

Josh

 

Aaron, Any luck on your truck today?

 

I'm not sure what the Neutral Safety Switch is, but the only things that weren't hooked up near my passenger side valve cover or on the passenger side at all where two smaller connections... they were RIGHT up against the firewall and sat directly beside where the Airbox would be (if I had an airbox) for the A/C. If either of those two are the NSS, then they aren't hooked up. However, if you're talking about the connections near the "I" & "S" solenoid, all of those are connected.

I'm wondering if this has something to do with the fact that a lot of the wires on my truck are butchered and stripped with no end connections (especially the A/C wires on my truck, because the cab is wired for A/C, but my engine doesn't have A/C).......... as well as the fact that my "new" tilt column's shifting linkage doesn't want to extend far enough to the transmission to reach the shifter on the tranny itself. In other words, my tilt column is sitting half way between netural (N) and (D), while the transmission is actually in park. Hope that doesn't make anyone confused, but I'm positive that it shouldn't matter... The original column used to be in park when the transmission was in park. I need to do some bending?

And no, I didn't get any luck on my truck. After I went back out from posting last time in this thread... I ended up getting something stuck in my eye, and it literally got stuck to my eyeball.

I've gone to the doctor to get it removed, but they ended up doing nothing at all but irritating it even more... Now I'm walking around with what looks like a very bloodshot black eye.

How did this happen? I was working on trying to get the truck started when something from under the cab fell into my eye and I couldn't tell what it was... but it hurt like a son of a !@#$%.

The reason I haven't had it checked out until now is because I had a very long and hard drive to another city where I'm currently in university.

I think when I head back in two weeks, I'll just simply switch out the 1979 harness that came with the cab to the original 1978 harness that came with the cab that is now gone... because at least the truck would run with the 78 harness.

I'm not sure where these wires are being crossed or what is happening, but I'm hoping that going back to the original harness (when the engine ran), will solve this "crossed wire/solenoid" problem. If it doesn't, I'm HOOPED! I'll be pushing my truck two blocks to get it where it needs to be... not fun..

Any suggestions? Or should I just go back to the harness that I know works?

 

Hope your eye gets better soon. Eye injuries are no fun at all.

Are both the 351W and the FMX of the 1972 year?

Do your reverse lights work when you put it in reverse?

Information and a member to contact about the body swap. https://www.ford-trucks.com/forums/9...ical-help.html

In this next one you will see the plug I am talking about. About 3/4's the way down the page there is a picture with a green circle, now my truck does not have the bypass plug (I am going to make one), but the connector I am talking about is just below and to the right of the green circle. I only want you to dig this deep into the NSS because it was the answer to the no start problem I was having with my build. https://www.ford-trucks.com/forums/6...ont-start.html

Another one. https://www.ford-trucks.com/forums/1...ty-switch.html

 

Yeah, you're quite right. The NSS seems to be the problem that I need to solve.

I don't remember any of the grey connectors near the firewall being unplugged, EXCEPT ONE.

But there's something I don't understand. In the photo that Dennis (M1llion) provided (with the green circle), the NSS was connected AT the passenger side from the passenger side wiring TO the driver side wiring. Why the hell does the wiring have that massive stretch across the back of the engine and firewall? It doesn't make much sense to string something like that across the engine engine bay... but anywho...

The connection I'm thinking of is in the EXACT same spot as the one in Dennis' picture and the same one as everyone is talking about. The only thing I don't understand is how my truck ever ran before, when it was never hooked up in the first place (original wiring harness).

My original wiring harness DOES NOT have a connection to make with that NSS on the passenger side firewall... UNLESS I string something from the drivers side to the passengers side like in Dennis' picture (with the green circle).

If the connection needs to be made to a 4-pronged grey connector, I can only think of one possible connection that could complete the circuit... but it's already hooked up to something on the drivers side. Is it possible I connected two pieces of wiring that actually aren't supposed to be connected together, when really I should be connecting one of those two together to the NSS on the passenger side???

This is all great info you've posted, and I hope you can follow what I've written as questions to you.

Thanks for the help so far! I think we found the problem, although I won't know until a week from now!

 

What you have written makes as much sense as what I have written. The 78-79 (C4 & C6) automatic transmissions had the NSS on the transmission and the 72 FMX was on the steering column I believe. I wonder if the OP wired up an older column and NSS to work with the FMX. The trick is to look for the 4 pin male connector comming from the truck wiring harness with the blue w/ red tracer wires coming from it. It seems that all these trucks even from the same year have little differences. I think you are on the right path and it'll just take a little more chasing wires and comparing harness'.

You'll get it, I'm sure of it.

You'll get home before me. I still have a couple weeks before I will get to mess with my truck again. I feel your pain. Well, most of it, as my eye does not hurt.

 

So if I eventually find the NSS (with the blue/red tracer wire), and hook it up correctly, that will solve my vehicle wanting to run in the "on" position instead of the "start" position?

If what you said is true about the 72 fmx being on the column, then I may have another avenue to look for when I get home.

When I wired up my new tilt column, I looked at the wiring harness that hung from the column directly and said "meh, this doesn't need to be hooked up". I may need to search into using my old column again until I can buy myself a Painless kit and REALLY get this wiring all sorted out, one by one.

I'll definitely go on a search for that red/blue wire with the 4-pin male connector as soon as I get home. I think the problem actually might be a multiple of things simply because I have a transplanted cab, engine, wiring harness (which is butchered at best..), and transmission.

I may have to convert my current cab back to the old column and wiring harness until I can figure out a way to correctly hook up the NSS on the new stuff, but at least my truck SHOULD run (in theory).

I'll keep you updated once I return home on the 16th. My truck is getting my attention first and foremost.

Thanks so much for your help so far. Please clarify my question in the first sentence of this post.

 

Not entirely, the starter engaging in the "on" position instead of the "start" position is only happening because you have the pink and brown wires in the wrong position on the solenoid.

The brown wire should go to the "I" Terminal and the pink (blue w/ red tracer). The brown wire has power in the "on" position, the blue w/ red tracer has power only in the "start position.

The big thing is finding where the NSS plugs into the factory harness. Once it's found the NSS can be bypassed for testing purposes, but I would not leave it like that as it is a safety concern. Bad things happen when vehicles start unexpectedly while in gear.

You might have to get creative making it all work and work safely. With the most focus on safety. I'm sure with what you know and the knowledge base on this site, you'll get there.

**EDIT**
If you simply want to see if you can get it to run.
1.) Make sure it is in park and use LARGE wheel chocks if you think you need them.
2.) Connect the brown wire back to the correct location.
3.) Use a jumper wire to put power from the + connection on the starter solenoid to the "S" Terminal on the solenoid (this should engage the starter).
Or you could make yourself a cheap remote starter from any 12v switch and wire it between the + connection on the starter solenoid to the "S" Terminal on the solenoid. (** for testing only**)

 

There's a thread on this from a while back that contains, among other things, a wiring diagram for a 79. It might help:

https://www.ford-trucks.com/forums/1...positions.html

 

Good luck on your truck this weekend Aaron.

Hope you get it up and running.

I'll be without computer and internet access starting this afternoon for about a week, I'll check in when I get back.

 

Okay... so here we are... Friday night.. I'm home and well...ish...

First things first. The NSS Switch has been located! And NO! IT WAS NOT HOOKED UP...

Here are the pics showing you my dilema... BECAUSE THERE IS NOTHING TO HOOK IT UP TO! How do we over-ride this sucker??? Ma baby has got to start!

Currently sitting like this (which is correct. Brown on I, Red (pink in my case) on S.)



This is the Neutral Safety Switch. You can see the red wires with blue indicators. I've shown these in the picture, although it may be hard to see with my terrible camera... This is the passenger side view, up against the firewall.



This is the confirmation of it being the NSS! 4-pronged, red wire with blue tracers!



Now for our little problem... My old wiring harness' NSS was never hooked up and never gave me any greif... Now my 79 wiring harness is in its place and I've been told that the NSS is what's holding me back from starting my truck.

There is NOTHING to hook up to the NSS. I've looked all over, high and low, drivers side, passenger side... everywhere. There are NO other 4-pronged connectors to hook anything up to! There is however, a four-pronged connector WITH ONLY THREE CONNECTIONS in it that COULD be hooked up. But that still isn't right.



How do I over-ride the NSS? I need my truck to start in the "START" position, not the "ON" position, like it currently is...

 

So... I solved my own problem.

Firstly, thanks to all of you whom helped me out with this. This was a massive struggle to get this damn wiring system from a 72 engine/tranny to work with a 78/79 wiring harness.

It's all figured out now, and I was able to get the truck running and stay running without the solenoid continually staying on. YAY!

It turns out that the original column had a NSS built into it... not sure by who (factory or PO), but its definitely in the column in my case.

My 72 FMX transmission has no NSS on it, so that's why there was nothing to hook up to my NSS which was dangling at the passenger side of the firewall.

To solve this problem, once I had the old wiring harness and column back in the truck, it turned over on the first try... no issues whatsoever... well... okay... it did stall a bit.... but it ran!

 

Good to hear you got it running again.

I was away from the web for a while is why I did not answer your email.

Hope she keeps running good for ya.

For a temp fix just to get mine started I made a jumper wire to connect the pins that were connected to the red w/blue tracer wires. I made the jumper using a larger gauge of wire with most of the copper strands removed (making extra space in the insulation) and slid each end over the two prongs. Pretty crude, but it'll work in a pinch.