I've been putting this off for a while because I figured this would happen. For a long time now, the car will only start in park maybe 4 times out of 5, and I have to put it in neutral to start it. Recently it got worse, and the reverse lights stopped working. So I decided to replace it before neutral stopped working, too.

I put the car in neutral, removed the nut that holds the cable bracket to the switch, and removed the two bolts, and unplugged the wiring connector. Put the new one down on the shaft, installed the two bolts loosely, and put the nut on tight so the shifter could move the shaft back and forth, and plugged the connector in. Now, the car will only start when the shifter is halfway between park and reverse. Moving the shifter to each of it's positions does exactly what it's supposed to do, being in park, reverse, neutral, drive, etc.

The bolt holes are slotted. If I move the switch all the way clockwise, the reverse lights stay on in park, and it starts halfway between park and reverse. All the way counterclockwise, it starts in reverse, and no reverse lights. Halfway between, no reverse lights in park, and starts halfway between park and reverse (where I've left it for now).

Now what?!

I just bypass them by connecting the wires together. Chances are you never try to start your car in gear anyway. I even bypass the clutch switch on sticks. Theyre just a PITA.

see my cave, Neutral Safety Switch in trans section.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

I found that same procedure in the service manual, and used a 3/32 drill bit as per the instructions, but no matter how far I rotated the switch, the drill bit never went into the hole. Should I remove the two mounting bolts and keep rotating until the bit drops in?

Likely no....
Cable is out of adjustment or switch is bad.

switch is $20(BWD)-$66(ACdelco) at advance auto

Cable adjust see SM

Well I figured out the problem and it wasn't my fault! I took apart the old switch to see exactly how they work:



The white part slides back and forth in the housing on the pivot (the keyed shaft coming from the transmission). On the end of it, is a small impression where the drill bit would go, as described in the adjustment procedure. I used the exact size drill bit, put it in the slot, and used a piece of tape to be able to tell when it was in all the way on the new switch.





Here is the transmission, in neutral.



I tried putting the neutral switch onto the shaft, WITH the drill bit in the switch, so it couldn't rotate out of adjustment. The switch will not go on the shaft, because the mounting tab on the transmission, where the bracket is, interferes with it. you can also see the mounting tabs wouldn't be anywhere close to lining up with the bolt holes in the transmission



DIAGNOSIS: shitty Chinese part. Was a Standard brand part, came in a red box, from NAPA. Will look for another brand.

Wrong # or
Right # but wrong switch in the box.

Return it and take old one with you.

I'll use ns3.jpg and/or ns2.jpg in my cave. Your pictures are better the one I have.

Went to swap it for another one, the new one had the same problem. Went to another store, bought an AC Delco, and took a picture to show exactly what the problem is/was:



You can see here, both switches in the neutral position. The Standard brand part apparently has the white part keyed or clocked incorrectly. The AC Delco, on the other hand, is keyed exactly the same as the original I took off the car. I installed the AC Delco one, and didn't have to do any adjustment; the car starts in park and neutral, and the reverse lights only come on in reverse, as it should be.

DO NOT BUY the Standard part, part # NS37, or NAPA part # ECH NS6557. The one that worked was AC Delco part # D2202A

[This message has been edited by RWDPLZ (edited 06-07-2012).]

The neutral safety switch provides three functions:
1. Start Condition only in N and D
2. Back up light activation in R
3. Signals the ECM that the trans is in D or L for proper fueling and closed loop operation.

On the 4T60e's the adjustment is aligned with a drill bit on the trans switch but on the TH125H I don't believe that this method is used.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
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quote Originally posted by rogergarrison: I just bypass them by connecting the wires together. Chances are you never try to start your car in gear anyway. I even bypass the clutch switch on sticks. Theyre just a PITA.

which wires do you connect to bypass the swich?