Need help with Neutral safety switch and B/U lights

[DanMcG]

Here's what I've got: 77 k10, 6 cyl and was a standard with shifter on the floor. Now it has a 400 auto trans. and a B&M auto floor shifter. it still has the original column that doesn't lock in place when the keys off, The key cylinder sticks and turns hard sometimes. I've got the purple and purple w/white stripe going to the shifter, plus a switched 12v wire.

My problem is the neither the NSS or B/U lights work and I really don't know how they work. are the open circuits and the shifter grounds them as they are in position. ( I get no power through the purples anytime.) I thinking they complete the circuits in the switch but I could use a schematic or two of the switch if anyone has one, or at least point me in the right direction. I've looked at the elec drawings here and other sites but still confused

thanks Dan

 

[1987 GMC Jimmy]

@chengny

 

[DanMcG]

ok so I figured out the back up light problem, whoever did the swap never hooked it up! The wires are probably under the truck just dangling near the transmission. The NSS is connected to the shifter, I'm just not sure if it's landed on the right terminals my ohm meter is dead and it started raining again, so I'll look into it tomorrow.

I got a couple questions if anyone knows,
I'm guessing the nss switch should be normally open?
And in 77 the lock cylinder should lock up the steering wheel when in park and the keys off. Correct?

 

[DanMcG]

I'm surprised I stumped the membership here, thanks for the help. I figured it out myself, it just took longer without any outside input.

 

[RustyPile]

I'm surprised I stumped the membership here, thanks for the help. I figured it out myself, it just took longer without any outside input.

Dan, I can't speak for the others here, only myself.. I've been a member only a short time but one of the things I've learned is most of the guys here don't "spoon feed" solutions to problems.. Rather, they tend to take on the role of teacher or instructor.. Part of the fun of owning an old vehicle is WORKING on it, and figuring out all the nuances..

I've installed many after market shifters over the years. One thing about B & M is they include very comprehensive installation instructions that include electrical diagrams.. I'll cover a couple issues you addressed in one of your posts.. The purple wires are hot only when the ignition switch is in the start position, and then only when, in the case of a standard shift, the clutch is depressed, and in the case of an automatic, the transmission is in either park or neutral..

You never said anything about whether or not the NSS and back-up lights worked before you started making changes.. Your comment about the "wires dangling under the truck" leads me to believe you haven't thoroughly checked the wiring before coming here. Did you actually expect someone to reply with "Check for dangling wires.."?. And please don't hold anyone here responsible for your tools being broke or "dead"...

To end this on a more positive note..... Your sticking key cylinder could be due to a couple things.. My first item to note is your key is probably worn quite a bit and no longer makes contact with the tumblers.. The worse solution to this problem is making a copy of that worn out key.. The new key won't work any better.. Same thing applies to the lock cylinder.. You can probably cure the whole thing by replacing the lock cylinder and key.... I preface all this with the disclaimer: Hopefully no one messed up the column ignition switch and accompanying linkage when making the swap from standard shift to automatic..