Neutral safety switch-Relay needed?
 

Hi Guys... new here, but have owned a whole lot of Mopars.

My question has to do with my 340/727 which I have run for over 15 yrs. without a neutral safety switch, but want to add one now. I have the 340 in a 1950 Ford pickup with MSD ignition... very little in the way of stock Mopar wiring harness... (hand crafted from GM harness + my own wiring)

I have no relay for the starter, simply used a 12ga wire to the switch in a GM steering column, then to the starter. I know the center pin on the trans sending unit normally grounds the relay (on a mopar) in Neutral or Park.

Can I just run a wire off the 12ga starter wire to the center pin or am I missing something? Wouldn't that also ground out the starter in Neutral/Park? Do really have to use a relay as most claim?

Any help would be appreciated.
Thanks, Del

There are a couple of ways out of this, DEPENDING on your shifter. Some aftermarket (B&M, etc) shifters have a NSS on the shifter or at least an optional place to put one.

If you use the Mopar switch, (3 terminal) the outer two switch the backup lights, and you are correct, the center pin is ground in park/ neutral

Probably the best way is to simply do as Mopar did --use a Mopar starter relay. Just about any mid 60-to mid 80?? switch for an auto trans, the only difference in all those years is the mounting ears. Just make sure it's four terminal.

the "big stud" connects to a battery feed, and if you use a "nice big" feed like Mopar, you can also use that stud as a take-off point for other accessories you might add

The "square" terminal goes to the S terminal on the starter

Either of the push on terminals goes to your start wire from the key

The remaining push-on terminal goes to the center pin of the neutral switch at the transmission.

One 'o these here:

https://contentinfo.autozone.com/zne...CR604/image/4/

Easiest and the best... I have had problems with the NSS in shifters.... The relay works best!!!!!

I am pretty much decided that the mopar relay is the way to go!!! Available at NAPA... and pretty simple to set up.

Thanks again...

I used a wire to 12V and through a LED & a resistor on my dash, to the grounding pin (#2). When I have neutral, the Lil' light turns on. Twenty minutes and $ .50 of gear.

If you are handling current to the starter, then, the box above is the way to go.
I use lugs to transfer current to my Acc. from here.

Heat-soaker GM starters benefit from using the FORD STARTER RELAYS though.
http://www.oldengine.org/unfaq/solenoid.htm

help with nss please
 

I'm in a similar situation to the gentleman that posted earlier. I have a 86 w150 truck with 78 440/727 drivetrain. I completely gutted the wiring and replaced it with a harness from hot rod wires. I tried wiring in the relay like someone posted with the solenoid wire under the square terminal, the center wire from the nss on one of the tabs and the key wire on the other tab. With the key in the start position I have 12v on both the key and nss tabs but nothing on the square terminal with the solenoid wire. Any thoughts suggestions would be greatly appreciated.

If you have 12v on both "push on" terminals, the NSS is not grounding. The "series circuit" of the relay coil (the push on terminals is:

Key start wire -- push on terminal --through the coil -- push on terminal --to ground through the NSS

If the center pin of the NSS is not grounding in park/ neutral, you have

bad NSS

misadjusted shifter

something bent in the internal rooster comb (rare)

wiring problem, ie bad connection

Wiring question
 

Thank you for the help with the NSS. I have another question with some of the wiring coming from the steering column, I apologize in advance if I'm not formatting this right or asking too many questions in one post. From the ignition switch (low end of column), I have the Red, blue and yellow wires hooked into the new harness and the truck starts and runs fine. I'm using a new HEI distributor with everything internal so I've eliminated a bunch of the interconnections in the engine bay. My question is this....I have nothing connected to the pink/black, grey/black, black/white or black/red wires off of the ignition switch. Are these wires necessary or can I just cap them off? Than from the steering wheel there are three wire bundles, one bundle of 8 larger gauge wires, one bundle of 4 small gauge wires and one group of two wires. I have the new harness hooked into the bundle of 8 wires and turn signals, flashers etc are working normally....so what's with the other two bundles that I have nothing hooked into? Should I have anything hooked into those two bundles? Thank you for any thoughts/help.

I'm going to be no help on this one as I don't have access to an original wiring diagram, which you need for the color of your original ignition switch/ column wires.

It is IMPORTANT however, to be certain of several things:

Traditional, at least older Mopar "ignition run" wire from the switch used to "go dead" by design when the key was twisted to "start."

So the only ignition voltage during cranking was supplied by the coil resistor bypass circuit, traditionally brown on earlier cars.

The bypass circuit is and MUST be separate from the starter relay "start" wire, used to be traditionally yellow.

If you get the "start" wire interconnected with the bypass circuit, you will be putting a load on the ignition circuit anytime the trans is in park or neutral (NSS is energized) and this may also feed back and "try" to keep the starter engaged.

Some of the wiring to/ from your column is for things like the

horn button

key - buzzer

key light

sometimes things like time delay for the dome/ etc light

shift quadrant light, etc.

Curious if you would mind walking me through this set up, sounds like a great idea! I have a denso mini starter with one charge wire and a constant 12v battery lug and want my NSS to control charge wire through IGN switch. Thanks