What do these wires do? Neutral/Safety Switch
 

Hello,

My reverse lights have not worked since I bought the truck. (78 K10, auto)
After tracing down the wiring, I found that my neutral safety switch is totally missing. New one on the way...

So I'm pretty sure the light green and dark green connector is for my reverse lights.

Then there are the yellow and purple/white, which have been connected together. This if for the start circuit?

Then that leaves this purple wire all by itself not being used. Does this belong on the neutral safety switch?

Thanks!

Re: What do these wires do? Neutral/Safety Switch
 

The 2 purple wires are the starter circuit. The yellow wires has been added. Does it go to the starter?

Re: What do these wires do? Neutral/Safety Switch
 

i believe mine were yellow and purple, 82 dually. my coloum was worn out so it was hard to line up the shift to start it so i looped the safety switch. just have to remember to not staart it in gear lol

Re: What do these wires do? Neutral/Safety Switch
 

79 auto

Re: What do these wires do? Neutral/Safety Switch
 

First image is the Backup light plug.
Not sure where the yellow wire came from... Got an extra ignition switch plug?

1978 PPL/WHT is Circuit 5 the start position on the ignition switch. PPL Circuit 6 goes to the bulkhead plug and then the start lug on the starter solenoid.

1979 YEL is Circuit 5 the start position on the ignition switch. PPL Circuit 6 goes to the bulkhead plug and then the start lug on the starter solenoid.

You can find the GM schematics in my sig.

BTW according to the schematics it shouldn't start.

Re: What do these wires do? Neutral/Safety Switch
 

I need to look at my 78 i dont ever remenber seeing a neautral switch with different color wires till now.

Re: What do these wires do? Neutral/Safety Switch
 

Not sure when they changed them but my 78 has 2 green wires.

Just now saw the post above, there's my answer.

Re: What do these wires do? Neutral/Safety Switch
 

knew i'd seen yellow but couldn't find the 78 before,just took another pic
78 auto

Re: What do these wires do? Neutral/Safety Switch
 

Hmmm, the plot thickens.

So 78 has both wires purple, in the start circuit.

It's almost like a 79 steering column is installed?

I'm going to have to trace some of these down and let you know what I find.

Thanks guys!

Re: What do these wires do? Neutral/Safety Switch
 

Just an update: The purple wire that is not currently being used must have gone bad at some point an PO just left it there. He then ran a new yellow wire to the starter.

Just got my new Neutral switch, connected everything and success! We have reverse lights.

Thanks!

Re: What do these wires do? Neutral/Safety Switch
 

Bump for N2Trux

Re: What do these wires do? Neutral/Safety Switch
 

Thanks for the bump. I will be back under my dash soon.

Re: What do these wires do? Neutral/Safety Switch
 

What I was able to determine after in depth investigation is the plug that I have loose doesn't go anywhere. It has a jumper built, so it goes no where.

Re: What do these wires do? Neutral/Safety Switch
 

I'm reviving an OLD thread because it has the good info...

My question is what holds the switch to the column? Can I buy the clips in motornut's picture?

Attachment 2392888


I'm converting my 1980 C20 from manual to automatic and this is what my manual trans safety switch looks like. Seems I'll be able to transfer the plug with the purple and yellow wires straight from the manual to the new automatic switch and I will have Park and Neutral safety.

Attachment 2392890

This is what the automatic trans switch looks like new from rock auto.

Attachment 2392889

The wire for my backup lights is under the floor hump near the shifter. No sweat to extend those wires to the automatic switch but can I find a plug and re-pin it? Or will I have to just spice wires (not as pretty)?

Any clues would be appreciated

Re: What do these wires do? Neutral/Safety Switch
 

Here's some pictures from a Haynes manual on the subject. Talks about screws but looks like I need clips of some sort for the screws to screw into.

Attachment 2392910

Attachment 2392911

Attachment 2392912

Re: What do these wires do? Neutral/Safety Switch
 

Those "clips" are called J-nuts, available at most hardware stores... Also here:

https://www.classicindustries.com/sh...parts/?q=J-nut


The neutral safety switch isn't something special, GM used it for years.. O'Reillys and other auto suppliers have them sitting on the shelf.

Re: What do these wires do? Neutral/Safety Switch
 

Awesome..!! Thanks for that info it’s the little things that slow down some of these jobs and I like to be prepared ahead of time so the vehicle is off the road for the minimum amount of time.

I appreciate your help RustyPile great name by the way.

Re: What do these wires do? Neutral/Safety Switch
 

I've been using that screen name for about 30 years.. Originally, it described most of my projects.. Here lately, given my age, it more describes myself.

Re: What do these wires do? Neutral/Safety Switch
 

I’m with you brother

Re: What do these wires do? Neutral/Safety Switch
 

Just a tech tip-

If you don't care about the neutral safety switch being operational, you can use the yellow and purple wires for a kill-switch :)

Re: What do these wires do? Neutral/Safety Switch
 

I think I’d like the neutral safety switch. The reverse lights are lower priority but I’d like them too.

Neutral/Safety Switch
 

I'm still struggling with this. Has anyone got better pictures of how the neutral safety switch is attached to an automatic column?

I've bought an assortment of J-nuts but cannot see how they would fit or attach to the rectangular holes.

Attachment 2394285

The switch itself looks like it might go on if I had some kind of imbedded nut in there first.

Attachment 2394283

It does seem a little proud though, with those extra tabs on it.

Attachment 2394284

Also whatever fastener goes in there will need to be pretty short as there's not a lot of room for the shift tube to rotate.

My problem is that I am switching from a manual floor shift column to an automatic trans column and don't have anything to look at for reference.

Neutral/Safety Switch
 

Thinking about it I might just be able to attach it with a hose clamp....

Neutral/Safety Switch
 

Here is what the clips look like on a 1969 Camaro...these look more likely to work but are not right for our trucks...and I don't see any NOS/OEM clips listed anywhere.

Attachment 2394476

Attachment 2394485

Re: What do these wires do? Neutral/Safety Switch
 

Just following up here to say I attached my neutral safety switch using a hose clamp. Just plugged it all in and it works.!

Attachment 2397650

Attachment 2397651

Attachment 2397652

Attachment 2397653