Replacement neutral saftey switch

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brayden_winkles

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Short story long. In the process of rewiring my 73 duster everything done motor/gauges/charging system. Go to fire it up no dice. No continuity between nss middle prong and ground in park/neutral. I bought a new switch from rock auto standard motor products ns11 change it out with a bucket underneath doing the old nascar pit crew Maneuver, trying not to make a bloodbath of the garage floor.
Anyway i tested the new switch before hand on the bench with the ohm meter everything was good but if i tighten it anymore than 2 or 3 threads by hand it goes south, theres no continuity between reverse light pins. The switch is obviously longer not allowing the plastic plunger to come out for the reverse light portion. is there a better source for these than standard motor products? In the mean time ill tighten it up and carry on, but id like reverse lights to work off the transmissions switch.

Tldr. Replace nss with standard motor products ns11, switch obviously longer in transmission body portion, reverse lights dont work when switch tightened, need source for one thats not chicom.
 
There's two, maybe three, versions of the NSS/reverse lamp switches and connectors.
 
As far as i know the trannys never been apart. And it functioned properly in the past. Threaded portion is just a tad longer on the replacement they list. I Ordered another one off rock auto see what happens i guess.
 
What year is the transmission? If it's an early '68 or older transmission, they used different internal parts to run it's single wire switch. You can't just swap in a 3 wire switch in place of a 1 wire. The "rooster comb" inside is different too. If it's a late '68 or newer transmission, it time to pull the pan to see what going on in there. On a 3 wire switch, the center pin is for the neutral safety circuit. It just grounds the terminal when the transmission is in neutral or park. That allows the starter relay to work. In the reverse position, the outer two pin are connected internally to complete the BU light circuit.
 
You said it worked in the past? why are you changing it then?
My 72 B body had an earlier trans than I thought. The trans is from 68. I put a 3 pin NSS in and it worked but the reverse lights were on in D. I'm gonna search for a single post to correct it and just go with no reverse lights.
 
You said it worked in the past? why are you changing it then?
My 72 B body had an earlier trans than I thought. The trans is from 68. I put a 3 pin NSS in and it worked but the reverse lights were on in D. I'm gonna search for a single post to correct it and just go with no reverse lights.
the switch worked in the donor car it was in, tranny sat on the garage floor for a few years. Doesnt work now spring doesnt push out the plastic plunger anymore. 73 trans 73 car 73 replacement switch.
 
The metal body part is longer and so is the plastic plunger when its extended. its pushed in because i forgot to pull it out before taking the photo, but doesnt extend on its own anymore

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I don't see anything obviously wrong with the new switch. Are you sure you had it in reverse when you tested it? That's the only position that will close the switch to the backup lights. It has to be threaded in all the way for it to work right too. Is it just the backup lights that don't work now? The neutral safety works and the cars starts?
 
Yes and yes. I disconnected the shifter linkage even and pulled it through all the positions on the shift lever. Also Yes it has continuity on the bench and in the transmission in reverse, the problem it seems is when i tighten it more than 2 or 3 three threads by hand it goes open circuit. im going nuts pulling my hair out chasing my tail.
 
Yes and yes. I disconnected the shifter linkage even and pulled it through all the positions on the shift lever. Also Yes it has continuity on the bench and in the transmission in reverse, the problem it seems is when i tighten it more than 2 or 3 three threads by hand it goes open circuit. im going nuts pulling my hair out chasing my tail.

Edit yes it is just the back up light pins that do not have continuity.
 
The metal body part is longer and so is the plastic plunger when its extended. its pushed in because i forgot to pull it out before taking the photo, but doesnt extend on its own anymore

View attachment 1715544864
With the crush washer You shouldn’t have to thread it in super tight. Maybe give you the shorter thread length and seal you need.
 
So, what I gather is that with the old switch, the car wouldn't start, but, the backup lights worked? And with the new switch, the car starts, but, the backup lights don't work? Strange. I'd try another switch or maybe add an extra gasket or two so the switch doesn't go in so far.
 
So, what I gather is that with the old switch, the car wouldn't start, but, the backup lights worked? And with the new switch, the car starts, but, the backup lights don't work? Strange. I'd try another switch or maybe add an extra gasket or two so the switch doesn't go in so far.
Yes. I ordered another switch today i dunno what else to say but weird.
 
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