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I have a 77 f250 400 c6 4x4, Im rewiring the whole truck right now. I went to connect connect the wires to my brake light switch and noticed the NSS.
I dont recall unplugging the NSS and I see that there is a plug with 3 male and one female going to the NSS. Where would I plug this into?
Is yours mounted up on the steering column, or down on the transmission? Seems like you're talking about brake light switch, so I'm guessing yours is under the dash on the column?
There is going to be (or should be at least) a matching connector with 1 male and 3 female contacts there under the dash too.
The two Red w/blue wires are for the starter relay (the neutral safety part) and the two Black w/red wires are for the backup lights.
Mine (4wd) is on the transmission and the matching plug on the chassis side of the harness comes through the firewall.
Yours is a 4x4 too, but being a '77 maybe yours is mounted different. If you're re-wiring the whole thing, are you using a pre-made harness, or rolling your own?
Is yours mounted up on the steering column, or down on the transmission? Seems like you're talking about brake light switch, so I'm guessing yours is under the dash on the column?
There is going to be (or should be at least) a matching connector with 1 male and 3 female contacts there under the dash too.
The two Red w/blue wires are for the starter relay (the neutral safety part) and the two Black w/red wires are for the backup lights.
Mine (4wd) is on the transmission and the matching plug on the chassis side of the harness comes through the firewall.
Yours is a 4x4 too, but being a '77 maybe yours is mounted different. If you're re-wiring the whole thing, are you using a pre-made harness, or rolling your own?
Paul
Im using a pre made one. Will i dont have any of the orginal wiring left in the truck except for whats attached to the NSS plug.
I think im going to run a toggle switch for backup lights. So thinking I might just remove or leave alone the NSS completely and not use it. If so What would I need to do so it starts? Or will it start anyways without it hooked up?
Depends on the harness. But unless you can guarantee that for the rest of the life of the truck it's never going to be driven on the street by someone other than you, and you don't mind the possibility of it starting in gear sometime and running over your foot (or other body part) then I would try to keep it connected. It's just one more step after all. Simply connect the wires and don't worry about it being a factory connector.
I watched a nice half-restored '50's pickup truck roll off the high end of a muffler shop lift one time. The guy had installed the exhaust system, then fired it up to check for leaks. Owner hadn't told him it didn't have an NSS and that it was still in reverse. Since the shifter was not stock to begin with, it was very hard to tell what position it was in anyway.
Luckily when the rear drive wheels fell off the rack it stopped most of it's rearward motion. Too bad for the fender and running boards, but at least it didn't fall the 8' to the ground!
And besides, even though a toggle works for the lights, it's still much easier to let the shifter do it automatically.
So two ways to proceed here.
If you're just going to leave it out, make sure the starter relay's "S" post is connected directly to the START post of the ignition switch. You're good to go from there.
If you want it to be safe for everyone, or pass inspection if your state ever goes to those, cut the 4-wire plug off of the wires and either splice or add connectors from the switch to the harness.
It's just an ON/OFF switch, so does not matter which wire goes where as long as you're close. What colors are on the harness? I'm assuming Violet (Purple) for the start wire? If so, run the Violet wire from the ignition switch to one of the Red w/blue wires, then the other ones goes to the starter relay.
Run your backup lamp circuit into one Black w/red wire, and out the other to the backup lamps.
A little more work for sure, but pretty straightforward for someone re-wiring their truck.
Depends on the harness. But unless you can guarantee that for the rest of the life of the truck it's never going to be driven on the street by someone other than you, and you don't mind the possibility of it starting in gear sometime and running over your foot (or other body part) then I would try to keep it connected. It's just one more step after all. Simply connect the wires and don't worry about it being a factory connector.
I watched a nice half-restored '50's pickup truck roll off the high end of a muffler shop lift one time. The guy had installed the exhaust system, then fired it up to check for leaks. Owner hadn't told him it didn't have an NSS and that it was still in reverse. Since the shifter was not stock to begin with, it was very hard to tell what position it was in anyway.
Luckily when the rear drive wheels fell off the rack it stopped most of it's rearward motion. Too bad for the fender and running boards, but at least it didn't fall the 8' to the ground!
And besides, even though a toggle works for the lights, it's still much easier to let the shifter do it automatically.
So two ways to proceed here.
If you're just going to leave it out, make sure the starter relay's "S" post is connected directly to the START post of the ignition switch. You're good to go from there.
If you want it to be safe for everyone, or pass inspection if your state ever goes to those, cut the 4-wire plug off of the wires and either splice or add connectors from the switch to the harness.
It's just an ON/OFF switch, so does not matter which wire goes where as long as you're close. What colors are on the harness? I'm assuming Violet (Purple) for the start wire? If so, run the Violet wire from the ignition switch to one of the Red w/blue wires, then the other ones goes to the starter relay.
Run your backup lamp circuit into one Black w/red wire, and out the other to the backup lamps.
A little more work for sure, but pretty straightforward for someone re-wiring their truck.
Paul
I'll check on the wiring color in the morning , but now the way you posted it , i just might go ahead and wire it all in. Just sucks they instructions i have only talk about tone purple wire going to some place , cant remember where they said, I'll relook it up also and get back to you .
Thanks for the help so far!!!!!!!
cut the 4-wire plug off of the wires and either splice or add connectors from the switch to the harness.
It's just an ON/OFF switch, so does not matter which wire goes where as long as you're close. What colors are on the harness? I'm assuming Violet (Purple) for the start wire? If so, run the Violet wire from the ignition switch to one of the Red w/blue wires, then the other ones goes to the starter relay.
Run your backup lamp circuit into one Black w/red wire, and out the other to the backup lamps.
A little more work for sure, but pretty straightforward for someone re-wiring their truck.
Paul
So yes i have a purple wire on my new harness. I get what to do with the purple wire now. So my only question is on the backup lamp one.
There is 4 wires that Im cutting the plug off on the NSS. two wires are red with blue stripe which you said to use for the ign with the purple wire. The other two are red with black stripe, So I guess this is for the backup light. So does the - and + wire from the backup light connect to the red with black stripe? If so I assume that it does not make a difference with one goes to which one?
Correct. You connect 12v to one of the Red w/black wires, then the other one runs back to the lamps. The switch is in-between and simply opens and closes the contact to let the juices flow.
Same for the Red w/blue as you said. One side from the key, the other side out to the starter relay. When it's in Park or Neutral, the contacts are closed and the power flows through the wire. Any other gear and the contacts are open and blocks the flow so that you can turn the key, but you will not get the relay clicking or the starter spinning.
Because it's only an "open/close" type of switch, it is not polarity sensitive, so does not care which one you choose as in to the switch vs out.
Correct. You connect 12v to one of the Red w/black wires, then the other one runs back to the lamps. The switch is in-between and simply opens and closes the contact to let the juices flow.
Same for the Red w/blue as you said. One side from the key, the other side out to the starter relay. When it's in Park or Neutral, the contacts are closed and the power flows through the wire. Any other gear and the contacts are open and blocks the flow so that you can turn the key, but you will not get the relay clicking or the starter spinning.
Because it's only an "open/close" type of switch, it is not polarity sensitive, so does not care which one you choose as in to the switch vs out.
Paul
wow, simple then. Then All i need now is to run 12v power for back up light side. I take it that the switch closes when placed in reverse so Backup lights turn on.
Thanks a million!!
Correct. They have the two separate functions, with different positions.
When in reverse it closes the contacts on the Red w/black wires and when in park or neutral it closes the contacts for the starter relay wire.
Does your harness already have a dedicated backup lamp wire? Or do you have to add that yourself?
Sorry I forgot, but did you say which harness you bought?
When I was wiring a couple of buddie's Broncos, I converted the 4-pin rubberized factory plug to a 4-wire Weatherpack connector.
Yes, it means that if the switch ever fails again, you have to transfer it's half of the connector over to the new one before you can install it. But that was a small trade-off for having a better, more repeatable and reusable connector, rather than having to find a good new or used factory type for the harness.
Seemed like a better idea at the time, and has not caused any trouble yet.
Interesting, them leaving out a common circuit like that.
They've got A/C, third brake light, power window, and two or three other non-essential high-end build components, yet leave out something that's been the law for every road-going vehicle for over 50 years now.
Anyway, I'd have to agree that you will need to make your own at least from the switch to the lamps. But they appear to have extra circuits to have you covered from the ignition switch to the neutral safety switch. Just have to choose which one is convenient and will work best for you.
1TonBasecamp so I came across a picture of what you where saying. Perfect match. Again thank you!! And of course the wire numbers are not for my wiring harness but the colors do match the plug.
So explain a little more about what we're looking at (good pic by the way) in that picture. You've got the NSS connector on the top, correct? Where exactly does the lower half come from?
Is it part of a new harness, that happens to have Ford wiring colors on it? Or is it left over from some part of the original harness?
And for another pic request, can you separate the two and show the contacts on the six-wire connector? Are there only four contacts, which is how the two are able to mate up still? Or are there six independent contacts?
Looks to me like two of the segments are paired up, so that the six wires actually fit into four locations. Is this correct?
If so, then it's probably simpler than it appears at first.
If you have the Dura Spark electronic ignition from Ford, the second Blue w/red wire in the lower connector is probably for the signal to the ignition control module. Not sure what the need for a spliced wire into the reverse lights would be though, other than perhaps for trailer wiring?
Both of those are just guesses though, until I find some info on a diagram.
In the meantime a quick voltage test on the lower half in the pic would be in order.
With the key ON check for 12v at the Brown looking wires, along with that White w/black stripe wire.
Then, with the key in START check for 12v on the Red w/blue wires.
If things follow normal functions, one position will have 12v in each key position.
Let us know the results, and I'll go look for an appropriate diagram.
Good luck with the arm! That sucks and probably still gets in the way of doing some of this work. But do what you can and see how far we can get.
