67 Neutral Safety wiring color

[Michael S.]

My apologies in advance because I know there are a lot of threads on the mid year power glide neutral safety switches, but I haven't seen anything on this point. My 67 PG neutral safety switch harness has a heavy gauge purple wire and the same heavy gauge gray wire for the starter circuit. All info I have seen refers to two purple wires. Also, I have seen NOS neutral safety switches advertised and sold in the past (aware they are long ago discontinued) with the purple and gray wires (see photos of prior sales items). My neutral safety switch has been bypassed by a prior owner and I'm just researching as I try to troubleshoot. I think I understand the connectivity but this wire color thing has thrown me a little. Anyone have any info on the wire colors (i.e. original install, service replacement)?
thanks,
Mike

[Michael S.]

Re: 67 Neutral Safety wiring color

I forgot to mention that my 67 NSS appears to be the correct configuration, except for the gray wire

[Stephen L.]

Re: 67 Neutral Safety wiring color

The switch for an automatic is actually 2 switches in one housing; the neutral safety switch and the back up light switch. The 2 larger wires are the neutral switch leads; one is gray and 1 is purple. These "interupt" the #12 purple wire which runs from the key switch (start contact) to the starter solenoid. I don't know where this connector is located.... AIM shows it in the engine compartment.

The second switch is connected to a connector located near the firewall in the engine compartment This connector will have a #18 light green and a #18 pink wire in the engine compartment going back into the car interior. Your switch connector should mate up to this connector.

Based on the AIM, I believe the routing of the wiring from your switch would be under the car to the engine compartment, as the associated connectors are located in the engine compartment. The backup light connection is close to the ballast resistor.

Good luck
Steve

Look in you AIM on page UPC-M35-A5 and UPC 12-C7 for connector locations

[Michael S.]

Re: 67 Neutral Safety wiring color

Thanks Steve. I may have missed something but I think the AIM shows 2 purple for the start "interrupt". I think the flow and the connections are pretty clear based on all the documentation and conversations, but seeing NSS with two different color configurations is just a curious issue that I have not seen discussed. I actually have one of each, in the car with purple and gray, and on my shelf, that has two purples. Pretty much a novice when it comes to wiring, so I could be misinterpreting.
aim NSS wiring.jpg
thanks,
Mike

[Stephen L.]

Re: 67 Neutral Safety wiring color

Can't say why the color difference..... Maybe the vendor ran out of purple wire. Connection wise there is no difference. Could be the change was made during a later year.... and the part# stayed the same as the functionality remained the same......

[Richard M.]

Re: 67 Neutral Safety wiring color

I agree with Steve that probably just a supplier issue and used Gray on one side and the switch will function properly as is. The connectors are correct regardless of wire color. I think the confusion is that M35 A5 shows the wires from the NSS as both being Purple(see AIM notation below), as well as the Wiring Diagram showing both Purple. It appears that (some)service parts have one wire as Gray. Either way, those are very rare switches.

If you're going to replace the switch and foresee the car being judged in the future, I would use the 2-Purple wire switch. It's a substantial amount of work to replace the switch and run the wiring under the carpet, kick panel and under the dash out into the engine bay.

As an aside..... Note that the 1967 AIM is actually in error regarding the notation..... "Connectors part of engine wiring harness....".

In 1967 the one Purple wire from the IGN switch was part of the main harness and went through the firewall grommet as a single 12G wire with its connector end near the wiper motor under the cowl area.

For pre-1967, this Purple wire from the IGN switch terminated at the firewall bulkhead connector receptacle. The separate Engine harness then carried the Purple wire from the mating bulkhead connector plug to the Purple wire connector under the cowl. Both Purple wires were part of the engine harness.

The reason for this change in 1967 was they used that previous Purple wire pin location in the bulkhead connector for the Brake Pressure Differential Warning switch Tan wire. Prior years didn't have that feature.

M35_A5.jpg

[Michael S.]

Re: 67 Neutral Safety wiring color

Thanks Richard. No, this will be a driver, not a judged car, but I like to have things as right as I can and understand when something is wrong, why it's wrong. I've got the interior and console out so switching out the NSS with harness won't be too bad. My thought is that I will use the one that works so I won't start the car, while simultaneously backing through the garage door. I have been a member for some time now, and understand the detailed discussions, with regard to "not typical", and was more curious about a different color wire, not being noted, particularly from a judging perspective. When I saw some of those old ads for NOS switches, with the gray wires, I thought I'd ask.
thanks again.
Mike