Neutral Safety Switch Mystery

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markweinberger

Not-quite-so-new-guy
Sep 3, 2021
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Many years ago I installed an Olds 455 and Turbo 400 trans in my 1987 Olds 442...I had to change out the console shift linkage with an older Cutlass to coincide with the Turbo 400 which worked out great except for one big safety problem...the car starts in park as it should, but also starts in the reverse position. I tried adjusting the neutral safety switch, to no avail, I tried another neutral safety switch from a 1984 Cutlass...same problem. The craziest part is I disconnected the Neutral Safety switch from the harness completely and the car still starts!....I always thought without a Neutral Safety Switch connected the ignition wouldn't work?!....I looked at my 1988 Pontiac Safari Station Wagon's Neutral Safety Switch (which I also installed a Turbo 400 in) and it's identical, and starts in park & neutral as it should....I was going to try a Neutral Safety Switch from an older GM car with a Turbo 400, but they don't fit in the column....what in the world am I doing wrong?
 

CopperNick

Comic Book Super Hero
Supporting Member
Feb 20, 2018
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It almost sounds like the linkage adjustment at the transmission needs to be revisited. Check me on this. You put the floor shifter in park, does it seem to be solidly in the park location or does it feel like the shifter wants to mover further ahead? Are you running a cable drive from the floor mechanism to the lever on the t-mission or is it a solid rod or rail like a column shift would use.

If you have adapted the cable shift from the newer t-mission to the older unit, you may have to head below and check the tension/adjustment in the cable. That cable should be fairly tight with little slop or play in it. It should also be solidly anchored or secured at both ends to keep the outer sleeve from moving around. To me it sounds like the lever on the transmission doesn't move completely out of park but is sort of sitting in no-mans land between the two gears in terms of the detent inside the transmission. Because it is on the fence, so to speak, the neutral switch is still active and the starter will initiate or spin as a consequence.

JUst me here, thinking aloud.



Nick
 

markweinberger

Not-quite-so-new-guy
Sep 3, 2021
7
5
3
Thanks for your thoughts Nick....But the linkage via the shift cable to the transmission and the column locking rod are all tight and shifting as they should...it goes solidly in all gears, I may ahve to live with the issue unless I can discover a Neutral Safety Switch which works....However, since the Turbo 400 never came in the G-Body (to my knowledge) there may not be a neutral Safety Switch which solves the problem.
 

Drkuhar

G-Body Guru
Sep 27, 2018
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Girard, IL
Many years ago I installed an Olds 455 and Turbo 400 trans in my 1987 Olds 442...I had to change out the console shift linkage with an older Cutlass to coincide with the Turbo 400 which worked out great except for one big safety problem...the car starts in park as it should, but also starts in the reverse position. I tried adjusting the neutral safety switch, to no avail, I tried another neutral safety switch from a 1984 Cutlass...same problem. The craziest part is I disconnected the Neutral Safety switch from the harness completely and the car still starts!....I always thought without a Neutral Safety Switch connected the ignition wouldn't work?!....I looked at my 1988 Pontiac Safari Station Wagon's Neutral Safety Switch (which I also installed a Turbo 400 in) and it's identical, and starts in park & neutral as it should....I was going to try a Neutral Safety Switch from an older GM car with a Turbo 400, but they don't fit in the column....what in the world am I doing wrong?
Cutlass did not have a true neutral safety switch.. it used a mechanical interlock that stopped the key from turning. The electric wires had to do with the computer and the computer controls on the original setup.
 
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ELCAM

Royal Smart Person
Jun 19, 2021
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I think their is a mechanical block in the steering column that is to prevent the start function of the ignition switch from working unless it is P or N. You will need to see what the ignition switch rod and the shifter bowl interaction is. See where it is going wrong.

NSS GM Tilt.jpg

Park slot and neutral slot in shifter bowl.

ShifterBowl.jpg


Work the floor shifter and see if the bowl turns with the floor shifter movements.
 
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markweinberger

Not-quite-so-new-guy
Sep 3, 2021
7
5
3
Cutlass did not have a true neutral safety switch.. it used a mechanical interlock that stopped the key from turning. The electric wires had to do with the computer and the computer controls on the original setup.
Thanks DrKuhar....I never thought of this, and since I disconnected the computer to operate an older Carburetor, Distributor and Turbo 400 versus the 200R4 transmission is would explain why the car starts with the Neutral Safety Switch completely disconnected!
 
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markweinberger

Not-quite-so-new-guy
Sep 3, 2021
7
5
3
I think their is a mechanical block in the steering column that is to prevent the start function of the ignition switch from working unless it is P or N. You will need to see what the ignition switch rod and the shifter bowl interaction is. See where it is going wrong.

View attachment 183161
Park slot and neutral slot in shifter bowl.

View attachment 183162

Work the floor shifter and see if the bowl turns with the floor shifter movements.
Thanks ELCAM....But the steering column locking pin only engages when I place the shifter in park & turn the key in the off position as it should....so I don't believe the starting in REVERSE is caused by that issue as the column is not locked at that point....I was thinking there's another switch somewhere I'm overlooking, but I can't imagine where. Thanks for the input.
 

markweinberger

Not-quite-so-new-guy
Sep 3, 2021
7
5
3
Thanks ELCAM....But the steering column locking pin only engages when I place the shifter in park & turn the key in the off position as it should....so I don't believe the starting in REVERSE is caused by that issue as the column is not locked at that point....I was thinking there's another switch somewhere I'm overlooking, but I can't imagine where. Thanks for the input.
....on second thought...you have a valid point within the column itself...it may be a simple shift lever adjustment to ensure the shift bowl is in the correct position, that appears to be my last option considering adjusting the Neutral Safety Switch has been ineffective.
 
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ELCAM

Royal Smart Person
Jun 19, 2021
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There is no other switch on this design. It is all mechanical. If the shifter bowl does not move it will likely be fixed in the park position and will start in any gear selected by the floor shifter.

StarterSystem ED.jpg

I think it has that note because anyone familiar with the older GM cars would be looking for the switch and not finding it and thinking WTF they left it out of the wiring diagram.
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
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That "neutral" switch found on top of the column is simply a reverse light switch. GM calls it a "transmission position switch" in the electrical diagram section among other names. Which is stupid because it's just an adjustable switch so you can match the reverse lights to come on when the transmission selector is in the reverse position. And in this picture, they use "Park Neutral" in there and it has nothing to do with those positions, in reality.

Reverse Switch Column Adjustment.JPG
 
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