Neutral safety switch question (I searched)

I am using a extreme duty built c6 from a 73 in my 79 towtruck, The 73 isnt tapped for the NSS.. which I could do,, but its a hassle,, drop pan.. drop valve bdy etc.. drill tap..linkage etc

I would rather make it into a manual switch by wiring it as a dash switch (on/Off). My back up lamps are already wired separately as there are multiple flood lights that come on in reverse (which go to a relay and power source)

My questions are these
1) I understand the safety risk because with this setup as it would be the drivers responsibility to make safe each time... (for me not an issue and a part of pre trip check each time)

2) Wouldnt this in essence be a kill switch that a car thief would have to figure out thereby potentially stopping an amateur?

3) A manual switch would be a jumper.. open/closed circuit.. correct?

4) Anyone confirm the NSS wiring colors for the 79? (AUTO)

I got this from search but it doesnt say what they are;
"It should go to a grey 4-pin terminal for the trans neutral/safety switch. This terminal has wires that are with 2-red with blue stripe, 1 double White with Purple Stripe, & 1 double Black with Red stripe."

Actually I think its different for the auto


Thanks

 

All of your thinking is correct. The NSS interrupts the RED with BLUE stripe wire going to the 'S' post of the solenoid. A simple 12-volt SPST switch will work. The only current that runs through it is the coil current of the starter solenoid.

The other signals in the pigtail that normally goes to the NSS are for the backup lights. You'll lose that too by not adapting the factory setup.

 

I have also been thinking about this too with my 77. It has a C6 without NSS but a 79 column. Right I am not running any sort of NSS. I was thinking about wiring it with the brake switch so that the brake must be pushed in in order for the truck to start. That way if it is gear, at least it won't take off with the brake applied. Not sure if that would work or not,just something I had thought about. Otherwise, the switch idea would be an option.

 

This is just my opinion (should have added this before), but the idea of a toggle switch for an NSS seems pretty useless. With no mechanical coupling to the gear selector, there's nothing forcing it to do its job. It relies solely upon the driver to operate it correctly, which isn't guaranteed, hence the reason for the original "behind the scenes" switch. A toggle switch offers no more protection than you the driver simply remembering to take the shifter out of gear prior to starting. You have to force yourself to remember something either way. Adding a toggle switch means drilling holes and adding wires for really zero benefit.

I'm not sure if the brake pedal idea would work easily either - there may be issues with that setup getting back-fed when the turn signals or hazards are on depending on how it's wired. It would take a little investigation. But for similar reasons, I wouldn't think it would be all that useful. If tapping the older-model transmission isn't acceptable, I'd look at making something home-made with a snap-action switch on the column, if possible.

 

You are right.. the switch would be usless ..but simply there as a " youre dumb" reminder.. put in park..put foot on brake..

I really like wiring into the brake idea,,, but as you said.. how to make it function..

I realize Im trying to take a short cut.. and its hard to outhink engineers...

I think street rodders face this issue all the time and I would think someone has a gizmo already designed that electronically addresses this.. plug and play... I havent found it but Ill keep looking

One thing I wouldnt mind is having LESS wires running around my truck

 

I do agree with trying to make something on the column work. I will look into trying to tap the existing tranny. It was just an over sight by myself when putting things together at the time. Since I have been the only one driving it, not such a big deal, but you never know when you leave it in gear or the kids have messed with something. I sure would hate something to happen.

I'd like to do some more research on the column idea. I did ask about trying to make an earlier style column NSS work on a later style column but never did get any good info.

 

How about a using pressure actuated brake light switch, or another brake switch. Use it to activate the ground trip on a relay. Like your horn circuit. Then use the hot on the relay to trip the solinoid. That way she won't start without your foot on the brake.

 

You can use the brake light wire to activate a relay , and use the relay to short the start wire. Keep in mind that as soon as it starts if you take your foot off the brake you are cruising :-)

 

You could probably fab a detent button when the shifter is in neutral it presses down on a pressure switch closing the start circuit.

 

C7TZ-7A247-A .. NSS (Motorcraft SW-600): 1967/77 F100/350 all A/T's, located on steering column.

D0TZ-7B097-B (replaced C5TZ-7B097-A & D0TZ-7B097-A) .. NSS Selector Lever, attaches to shift tube thru hole in steering column shroud, knife blade ends inserts into NSS - 1965/77 F100/350.

D8TZ-7A247-A .. C6 NSS (Motorcraft SW-1489): 1978/79 F100/350 & Bronco, located on transmission.