On my 1970 f100 ever since i got it it will start in any gear. Now that it is about ready to drive its starting to kinda bug me. Also i have no reverse lights since its a automatic trans so the reverse lights are in the switch. It appears that the pin broke on the steering column so the PO just wired the nss to the side. But now when I go to test the switch I get a hot wire going to it but no power comes out no matter where the slider is. Also when I give power to the other three prongs on the wiring harness side plug I still dont get reverse lights. What all is the problem here. Im assuming I need a new switch and pin but why do the reverse lights not come on when I give them power through that plug. Fuses are good and bulbs are good. Does anyone have a wiring diagram with this style switch. I couldn't find one. Thanks in advance!

 

There are 4 wires on that plug. Two for NSS, and two for back up lights. Trying to recall. Two have red stripes?, two don't? Something like that. I'm thinking the stripe ones match, the non striped or for other circuit.
The two for back up lights should have power on one side(with key on) and the other side goes to the lights out back.
I don't know the NSS wiring situation. I know if you hook them together it will crank, so I'm guessing one side has power with key on?

I have done stick shift conversions, so I've had to bypass the switch for NSS and also wired the back up lights to the shifter.


Here are the wiring diagrams:
Ford Truck Technical Drawings and Schematics - Section I - Electrical and Wiring

Here is the master harness:
http://www.fordification.com/tech/wi...-70_master.jpg

Next:
http://www.fordification.com/tech/wi...t-lights01.jpg

 

There are 2 black with red and 2 red with blue or green. I think. The one black with red has keyed power but the other doesnt . And when i jump the hot one to any of the others nothing happens. The PO must have snipped some wires somewhere. Cause i have the switch unplugged and nothing changed. Itll start in any gear and no lights.

 

I think the matching stripes go together. If the one black on has power with key, my guess is that is back up lights 12+. Hooking them together should make the lights come on (with key on). If not, then something is cut elsewhere(or bulbs bad, sockets bad, etc).
The other two must be NSS. If those aren't hooked together now and it starts then something is patched elsewhere.

There is a 4 wire harness that comes out of drivers side firewall that goes to the rear along the left frame rail. That will have the wires for the tail lights.
1) LT/brake
2)RT/brake
3)parking lights
4)back up lights

Time to investigate that harness to see why lights don't work. If I recall there is a plug out front before it gets to the frame rail. Try unplugging that and adding 12v+ to each and see what lights up out back. Narrow the 4 wires to what they do.

 

Did you fix the PO bypass? If not then nothing is going to happen with the starter side yet.
The two Red w/blue stripe wires are the NSS wires. Ignition switch to NSS in START only (of course!), then NSS out to the starter relay's small "S" post.
You'll just need to find out where the power stops after you jump the two Red w/blue wires together. You already know that the ignition switch is directly wired to the starter relay, and that it will crank the engine, so you're at a big advantage over some. Follow the wire from the starter relay back to the firewall and behind the dash to find out where it was cut.

For the backup lamps, since you said that the bulbs have checked out good, you just have to do the same thing. Who knows what goes on in a PO's mind when they "re-wire for more power" like Tim "The Toolman" Taylor used to do!
Maybe the wires were run to a switch somewhere on the dash?

Paul

 

I havent traced the nss to the starter but what i think is the wire at the starter solenoid has been spliced. Also i have given power to the little black wires in the back on the reverse lights and they never came on. Does that meen the sockets are bad? Or does it need to be grounded better than that. The brake lights came on when i pushed the brake with the lights pulled out of the truck so i figured the reverse lights were the same.

 

Not sure about yours, but on Broncos the reverse lights were grounded separately, through their own wire with a small ring terminal to the body inside the tail light cavity.
Since on Broncos the backup lamps were an afterthought ('66 models didn't get them until later in production) maybe the pickups retained that design feature.
The reverse lamps were added later, but to keep them sealed the sockets and reflectors were weatherproofed with some kind of gasket that kept them from grounding through the rest of the housing like the running and break lights did. Hence the 2-wire socket with dedicated ground wire for the backup lamps.

It rarely fails it seems, but under a 40+ year old truck anything is possible. I would trace the wires right from the firewall connector, along the frame, to the tail area to make sure that there are no pinches, kinks, melted spots from being too close to exhaust, or any other defect (including PO modifications!). It's a normal procedure these days because so much can happen to the wires mounted along the frame.
Don't know if yours has dual exhaust, but I can't count how many times I've see "custom" exhaust run too close to the brake lines, wires and fuel lines on the driver's side frame rail. Causes all sorts of mischief.

But of course, inspect the sockets too. Didn't mean to ignore that possibility. Tail light components can get pretty weathered.

Paul

 

D0TZ-7B097-B (replaced C5TZ-7B097-A & D0TZ-7B097-A) .. NSS Selector Lever / Obsolete

1965/77 F100/350.

GREEN SALES CO. in Cincinnati OH has 10 = 800-543-4959.

CARPENTER NOS OBSOLETE PARTS in Concord NC has 110 = 800-476-9653.

This lever has a knife blade end that fits into the NSS .. It's notorious for snapping off.

The NSS (C7TZ-7A247-A / Motorcraft SW-600) is the same 1967/77 F100/350 available from any auto parts store.

 

As long as one sprays some white lube or other lubricant into the NSS every now and then these switches hold up pretty good. But if this isn't done then there is a bit of a design flaw that always leads to the NSS failing. Inside there are 2 brass ***** that are the contacts for the electrical continuity. Due to a lack of lubrication these stop rolling and begin to wear grooves in the ***** and the contacts. Soon the no longer make electrical contact.

I open the switches, clean them up, replace the brass ***** with steel bearings that I buy at Ace, lube the sliding parts well with silicone grease, and reassemble.
It would be possible to make new contacts but it would be a royal PITA.
I'm not to interested in paying $90+ for a replacement from the auto parts stores. But then it would be a "new" switch and has value there.

I found the NSS missing on my wife's '71 SportCustom and the harness cut and spliced allowing it to start in any gear. Fortunately I have a few spare NSSs so I rebuilt one for her.

 

where is this NSS located please. i know it's on the column, but is it under the turn signal switch? and where is that 4 wire connector at? thx (1974). Nevermind, found them, right in plain sight. Doesnt appear that my switch is working because it's getting power in and nothing out. I"m going to try to rebuild it per above.
Well, sad face. i took the switch off, it appeared stuck, i lubed it up, it worked in my hand, i put it back on, it dont work. WHY? cause the little lever that sticks up out of the steering column and moves that rod back n forth, is snapped off from the steering column. Does anybody know if that part is replaceable or not?
HAPPY FACE yes it is. #22 on this LMC diagram: https://www.lmctruck.com/steering/st...umn-components''
It shows this Pin, Neutral Safety, with two holes in it. one on each side. This is the part that's broken. Can anybody tell me if this can be replaced without removing the column? thx ed; it can, i did it with a small screw driver but i had to remove the brake pedal to do it.