C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Bypass neutral safety switch

Old 11-06-2013, 05:36 PM
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jnorth
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Default Bypass neutral safety switch

How do I bypass the neutral safety switch at the switch?
Old 11-06-2013, 06:23 PM
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MrWillys
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Connect the two wires together. I would not do this other than for testing though. It's dangerous to have it start in gear. Don't ask how i know this?
Old 11-06-2013, 06:24 PM
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DUB
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I would not recommend it. The neutral safety switch is there for safety for ONE....and also this switch is used by the computer to tell it if it is in (Park/Neutral) or a (Drive) gear. The computer "thinks" that is is in PARK...and you are showing a throttle position angle and a vehicle speed. It will "freak out" and more than likely kick up a code...or start running "funny".

Other than that...SORRY...I do not modify around any safety feature...it is a liability thing for me.

DUB
Old 11-06-2013, 06:33 PM
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Originally Posted by DUB
I would not recommend it. The neutral safety switch is there for safety for ONE....and also this switch is used by the computer to tell it if it is in (Park/Neutral) or a (Drive) gear. The computer "thinks" that is is in PARK...and you are showing a throttle position angle and a vehicle speed. It will "freak out" and more than likely kick up a code...or start running "funny".

Other than that...SORRY...I do not modify around any safety feature...it is a liability thing for me.

DUB
Not too be rude, but this is not true. The neutral safety switch allows 12 volts to pass when contacts are engaged. The park / neutral switch completes a ground signal when in par or neutral. Two completely different switches.
Old 11-06-2013, 06:36 PM
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jnorth
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I completely agree, this is for testing purposes only. So connect the two larger wires together? The purple and yellow?
Old 11-06-2013, 06:42 PM
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Why not just put a test light on the purple to see if it has power when cranking. Maybe not enough arms?
Old 11-06-2013, 06:50 PM
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No power when cranking
Old 11-06-2013, 10:59 PM
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Originally Posted by DUB
also this switch is used by the computer to tell it if it is in (Park/Neutral) or a (Drive) gear. The computer "thinks" that is is in PARK...and you are showing a throttle position angle and a vehicle speed.
It will "freak out" and more than likely kick up a code...or start running "funny".
Is only a indicator to the ECM so it can adjust the RPM for being in or out of gear.
There is no feedback or error codes for it working or even being wired up.
With my aftermarket shifter, I have not had that indication to the ECM for 8 years
Old 11-06-2013, 11:00 PM
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Originally Posted by jnorth
No power when cranking
Year model helps
Old 11-06-2013, 11:06 PM
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Originally Posted by vetteoz
Is only a indicator to the ECM so it can adjust the RPM for being in or out of gear.
There is no feedback or error codes for it working or even being wired up.
With my aftermarket shifter, I have not had that indication to the ECM for 8 years
Then you have tolerated substandard operation, and are unfamiliar with the different tables and values dependent on whether the vehicle is in or out of gear.
Honestly, you have lost some of my respect for you in this post. Unless, this is a manual car?
Old 11-06-2013, 11:08 PM
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Originally Posted by vetteoz
year model helps
1990
Old 11-06-2013, 11:28 PM
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Originally Posted by MrWillys
Then you have tolerated substandard operation, and are unfamiliar with the different tables and values dependent on whether the vehicle is in or out of gear.?
It primarily goes 1/4 mile at a time so it doesn't spend a lot of time idling out of gear , usually WOT
Old 11-06-2013, 11:33 PM
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Originally Posted by jnorth
No power when cranking
The starter enable relay is wired between the Ign switch and the NSS
Check for power on the yellow wire at the relay when key in start position
Check for power out to the NSS on the yellow / blk wire

If no power on the yellow at relay check for 12V out of the Ign switch on the same wire
Old 11-06-2013, 11:35 PM
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Are we still talking about my car guys? I don't want to get in the middle of anything, but mine is a 1990 automatic car.
Old 11-07-2013, 02:43 AM
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Originally Posted by jnorth
Are we still talking about my car guys?
Refer post # 13 above
Old 11-07-2013, 04:19 AM
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Cliff Harris
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Originally Posted by MrWillys
The neutral safety switch allows 12 volts to pass when contacts are engaged. The park / neutral switch completes a ground signal when in par or neutral. Two completely different switches.
A more accurate description is "two parts of the same switch". There is only one switch assembly mounted on the shifter. It also controls the backup lights.
Old 11-08-2013, 06:15 PM
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Originally Posted by vetteoz
Is only a indicator to the ECM so it can adjust the RPM for being in or out of gear.
There is no feedback or error codes for it working or even being wired up.
With my aftermarket shifter, I have not had that indication to the ECM for 8 years
You need to read the service manual. Or re-check your data.

AS written in a 1989 Factory Service manual Page 6E3-C1-3

"The Park/Neutral (P/N) switch indicates to the ECM when the transmission is in park or neutral.This information is used for the TCC and the IAC valve operation.

IMPORTANT
Vehicle should not be driven with park/neutral switch disconnected, as idle quality will be affected and a possible false code 24 (VSS).

See section "8A" for more information on the P/N switch, which is part of neutral/start and backup light switch assembly".

ALSO:

In a Factory Service Manual for a 1993 Corvette. The IS a CODE 72 that deals with the gear selector switch.

DUB

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Old 11-08-2013, 06:18 PM
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Originally Posted by jnorth
Are we still talking about my car guys? I don't want to get in the middle of anything, but mine is a 1990 automatic car.
Did you finally get it to crank???

DUB
Old 11-08-2013, 06:48 PM
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Originally Posted by DUB
You need to read the service manual.
There are documented faults in the FSM
Originally Posted by DUB
"The Park/Neutral (P/N) switch indicates to the ECM when the transmission is in park or neutral.
Just repeating what I already stated above in post # 8

Originally Posted by DUB
This information is used for the TCC
Seeing the TCC is only activated when the car is in motion unlikely it will engage with the car stationary regardless of whether the ECM
knows if the trans is in or out of gear..............

Originally Posted by DUB
which is part of neutral/start and backup light switch assembly
Which both Cliffy and I previously stated ;
you were the one implying that bypassing the NSS being discussed in this thread
"also this switch is used by the computer to tell it if it is in (Park/Neutral)"
would affect the ECM

Last edited by vetteoz; 11-08-2013 at 06:54 PM.
Old 11-08-2013, 08:43 PM
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Originally Posted by Cliff Harris
A more accurate description is "two parts of the same switch". There is only one switch assembly mounted on the shifter. It also controls the backup lights.
Cliff,
More like 3 switches in one? Mine is a B&M and they're separate.
One allows a load to pass to the starter in Park / Neutral.
One provides a signal for reverse lights (I don't know if it's a ground, or load).
Another provides a ground signal when in Park / Neutral. It is possible to be a single unit, but it does 3 completely different things.
Scott
Vettoz, you got a schematic of this?
http://www.oreillyauto.com/site/c/de...0039&ppt=C0335

Last edited by MrWillys; 11-08-2013 at 08:52 PM.

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