Help Identifying Switches

[Taylor309]

Hey Guys,

I'm currently re-wiring my truck with a new harness and I need some help,

Can anybody tell me what these two switches are? I'm inclined to say the two pronged on the steering column is the neutral safety switch?? The old harness was a rats nest and I don't remember what I pulled off there.

The truck is a 71 GMC 4wd with a manual transmission. I don't see any switches on or near the clutch.

Also, if that is the neutral safety switch I know one of my wires would be the purple coming out of the ignition switch, would the other come from the starter?

Thanks in advance!

[lil hoodlum]

Yes, the one on the column is the neutral safety switch.

The other one is the horn relay.

[Sheepdip]

Originally Posted by lil hoodlum

Yes, the one on the column is the neutral safety switch.

The other one is the horn relay.

I can't say that I have ever seen a NSS for a manual shift on the steering column, all the ones I have ever seen interact with the clutch pedal.
I'm here to learn and maybe I'm in left field, but please enlighten me if there is such a beast.

[lil hoodlum]

Unless it is a floor shifted model, isn't the transmission still shifted through the column whether it is an automatic or three on the tree?

Maybe I'm wrong but the set up was the same on my 1968 C10 with 3 speed manual.

[Sheepdip]

Originally Posted by lil hoodlum

Unless it is a floor shifted model, isn't the transmission still shifted through the column whether it is an automatic or three on the tree?

Maybe I'm wrong but the set up was the same on my 1968 C10 with 3 speed manual.

Could very well be, I don't know and have never seen one but if you got one it must be..... I learned something today!

[RustyPile]

More than likely, the switch on the column is the back up light switch..

[special-K]

I don't think I've ever had a manual 67-72 with a neutral safety switch. That came later. At least having to depress the clutch to start did. And you can crank them while in gear. So what purpose would a NSS serve anyway? A NSS would have two wire in/two wire out. I believe this is the reverse light switch. I'm unfamiliar with it. But maybe that's because I mostly mess with 4spd trucks (switch on trans/2 wire). I've had a few w/3spd but never learned any lessons in that area

[Taylor309]

This is a floor shift model manual. The backup switch is on top of the transmission which would explain only the need for two prongs on this mystery switch. I finished up my ignition wiring last night and ran my ignition and starter through this switch so I’ll find out here in a couple of days if it’s a NSS or not...

[71gmcC15]

My 71 gmc 4 speed does not have a NSS. Yours should not ether. Colum could have been swaped out maby. Is it a floor shift column?

[Smitty]

Backup light switch for 3 speed manual transmission.

['68OrangeSunshine]

Maybe a PO swapped the steering column?
What's on the SPID? The code for an SM465 4-Speed is M20, I believe.

[71gmcC15]

Originally Posted by '68OrangeSunshine

Maybe a PO swapped the steering column?
What's on the SPID? The code for an SM465 4-Speed is M20, I believe.

Might not even be listed like mine. The floor bracing is the best way to know for shure.

['68OrangeSunshine]

Originally Posted by 71gmcC15

Might not even be listed like mine. The floor bracing is the best way to know for shure.

GMCs might be different from Chevys. Who knows? But on a Chevy the SM465 was an optional transmission.
A ''Standard'' truck, [no options] came with a 250 L6 or 307 SBC and a 3-on-the-tree Saginaw 3-speed. My '68 C/10 was ordered with a 292 L6 [RPO L25] and the SM 465 [RPO M20].
In 49 - 52 years who knows how many different trannies were worked in any one truck? Sometimes people changed out to a preferred type, and sometimes what was available or affordable. These trucks weren't always the toys of the leisure class. Some of them were worked plenty hard by folks who could barely afford to them running, but couldn't afford not to work.
I've had it since 1973. I honestly can't remember what generation # trans is in my Orange truck, now, but I've always gotten a Muncie 465. Much easier to keep it original and also I hate column shifters.

[71gmcC15]

Originally Posted by '68OrangeSunshine

GMCs might be different from Chevys. Who knows? But on a Chevy the SM465 was an optional transmission.
A ''Standard'' truck, [no options] came with a 250 L6 or 307 SBC and a 3-on-the-tree Saginaw 3-speed. My '68 C/10 was ordered with a 292 L6 [RPO L25] and the SM 465 [RPO M20].
In 49 - 52 years who knows how many different trannies were worked in any one truck? Sometimes people changed out to a preferred type, and sometimes what was available or affordable. These trucks weren't always the toys of the leisure class. Some of them were worked plenty hard by folks who could barely afford to them running, but couldn't afford not to work.
I've had it since 1973. I honestly can't remember what generation # trans is in my Orange truck, now, but I've always gotten a Muncie 465. Much easier to keep it original and also I hate column shifters.

He is a three I started on the subject

http://67-72chevytrucks.com/vboard/s...d.php?t=779161

['68OrangeSunshine]

Originally Posted by 71gmcC15

He is a three I started on the subject

http://67-72chevytrucks.com/vboard/s...d.php?t=779161

Thanks. I looked at that. I guess the proof would be the lack of anyone having a baseline GMC [unmolested] with a 3-Speed Saginaw and column shifter.
Of course there's always the weird codger who orders his new GMC truck with a Saginaw because he likes them. But that truck's SPID would have an RPO code for the 3-Speed, as a special order. [I don't know the Saginaw's RPO code offhand.] That is, if indeed, the SM420/465 4-Speeds were GMC's baseline in MYs 67-72.
For what it's worth, my '71 GMC K/1500 Jimmy has an SM465/NP205, factory. That's why I bought it. Chevy in the later phase of this vintage, was pushing the automatic tranny sales hard. I prefer manual transmissions, especially in a 4WD.

[Taylor309]

There are a couple of clues that could lead to the steering column being switched by a PO.

1. The steering wheel appears to be off a mid 80's Chevrolet
2. The column has what to me looks like where an ignition once went.

I didn't even think about the fact that it had probably been switched out. I don't think its the reverse lights due to that being on top of the transmission, but maybe it was on the vehicle it came off of?

Hopefully I'll be ready for start up on Thursday. I'll reveal the results here!