I am asking here first because Facebook can get too nasty sometimes. I have a 1970 Monte Carlo with a console (horse shoe) shifter. I have been having intermittent starting issues. I finally checked the Neutral Safety Switch. I have continuity in park and neutral for the two tangs for starting and reverse for the other set of tangs for back up lights. Nothing when in drive. I tried to adjust it and still no difference. I put a jumper wire for the ignition wire connector to bypass the switch and so far, it's flawless for starting. It is an NS7 switch. Is the switch bad? I was assuming since it was showing continuity where it should have it, the switch is good. How easy is it to replace this and get it adjusted properly? Obviously finding the sweet spot is an issue because I thought I had it figured out and it's not right. I am the only one that drives it unless it's in the shop for something and would like to fix it correctly. I am not real mechanical and get frustrated easily sometimes when people say it's an easy job and it kicks my butt. I've read to install it in neutral, but the bolt holes are slotted a bit so there has to be adjustment or room for error as I call it. I have even tried to jiggle the shifter while starting and it does nothing when it doesn't want to start at all. New battery, so I know it's getting plenty of juice. Sorry if this is long, but got lots of other stuff going on and am at wits end.

https://www.oreillyauto.com/detail/...-terminal-neutral-safety-switch/std0/ns7

I have found that when it becomes difficult to adjust the park neutral switch to work correctly all the time, it usually means there is slop in the levers and rods for the linkage, between the shifter and the lever on the transmission.

I would be looking for slop at each joint in the shift linkage between the shifter and the lever on the trans. It doesn't take much slop for linkage to not move the lever far enough, causing the switch not to make contact.

Drove it to the parts store to order a new switch. Dang thing didn't want to start again. Nothing when turning the key. Going to see what I can figure out today. Thought I was making progress............

Like poorboy said, is the shift linkage good and in adjustment? I have a Buick that sometimes doesn't start in Park, but will if you pull the shifter further up. It will also start if you play around with the shifter in neutral.

Two possibilities, the plastic bushings in the shift linkage are worn/missing and the remote possibility that the shift shaft has come loose in the rooster comb which will result in lost motion.

it's a Monte carlo John

Next time I'm under it and decide to drop the starter to check the connections, I may just run a 10GA wire from the solenoid right to the fuse box with a switch to bypass everything or run it to the ignition wire to the NSS. If I had to guess by the way it's intermittent, there's a wire somewhere making good connection most of the time and not so much other times.

So just to clarify a couple things

The NSS is on the shifter in this application?

Your intermittent no crank still happened with the NSS bypassed?

Does this only happen hot? Or will it happen on first starts too?

This really sounds like typical GM solenoid failure, but iirc you've already replaced it.

I'd make a high draw test light (generic turn signal socket and 1157 bulb with long leads and alligator clips) and put the bulb where you can see it. Test for power at the solenoid and work your way back to the ignition switch. The semi permanent installation will be present when the problem occurs, not hours later after a tow call. Sometimes with intermittent problems you have to do things like this.

OOPS.

Happens hot, cold, after storage, no rhyme or reason it seems like.

I have not replaced the starter or solenoid, but have removed it to mount a new battery cable to it. Connections there all seem good by looks. I now live alone and sometimes getting someone to turn the key so I can get a multi meter or test light on it is hard because there aren't a lot of people in the neighborhood I can ask and they come right over. I never thought of a test socket set up. I get power to the NSS every time I test it. However, I don't think I tested it when it wouldn't crank. I will keep a test light in the car as a reminder to check that next time. The NSS is in the console on the shifter so I can get to that easily to test it. I appreciate the input and keeping it simple for me.

i have been bit very hard more than once by the "connections look good by the looks of them" bug, [you can visualize where] and it even hurts just to think about that !
not saying that is the problem, but just relaying my own [hurtful] life experiences.
with that said, could the wires going to the starter have internal breaks or "green death" hidden somewhere in the insulation that can't be seen ? those particular problems have got me more than a couple of times.
just tossing stuff out there to look for.
whatever you find, please let us know.

Negative on just keeping it in the car. It needs to be hooked up full time.

By the time you gather things together the symptom might disappear.

Solenoids are a well known weakness on the older GM starters

This sure makes it sound a lot like the solenoid on the starter is dying. Years ago, you could buy replacement solenoids pretty cheap and they were not hard to change. If that starter has been on the car for many years, and a replacement solenoid is still available, I believe I would just go ahead ans replace the solenoid on the starter.

One more thing to add to the mix, GM starter solenoids get their ground flow through the starter brushes. Bad brushes lead to problems getting the solenoid to kick in.

What happened to my comment recommending that he post his question on a GM, Chevy or Monte Carlo site?

I don't know what happened to the comment, but I have asked on GM and Monte pages. 99% of them say it's the battery even though it's only a month old. They didn't suggest the simple test light with a socket idea. Most mechanical issues are resolved the same way Mopar/Ford/GM and you guys here seem to work on them and diagnose with simple explanations rather than tossing parts at it and being rude.

I like using the socket and 1157 bulb for a test light since it puts more load on the wiring than a traditional test light.

Weak wiring might have no problem lighting a regular test light, but the bigger setup will expose weakness.

Diagnosis costs time. Firing the parts cannon costs money.

To help eliminate the starter and solenoid jump the NSS plugs. That will allow it to start in any gear. If it works then the starter is ok and the problem will lie in the NSS or linkage adjustment. You could also hold the key in the start position and move the shifter between park and neutral. If it tries to start then you have a linkage adjustment issue.

I had a jumper wire on the NSS and it worked for a while and then it didn't. I am going to do the test light socket idea next. I believe the issue is from the wire from the NSS to the bulkhead or bulkhead to the starter or possibly the Solenoid. The wire from the fuse box to a momentary button then to the solenoid was working when I needed it, but that stopped as well. I replaced the button as it was an easy cheap fix. The old button wasn't testing continuity like it should. The button/wire set up was there when I bought the car.