Neutral safety switch
Thread Starter
5th Gear
Joined: Jun 2011
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Neutral safety switch
After rewiring my vette, it would not start in park, so I purchased a new neutral safety switch. It worked fine, except the backup lights remained on in every gear (did not happen with old switch). I returned the defective switch for a replacement. Upon installing the replacement, it started in park, however, when I set forth to adjust the position for neutral, it turned the engine over while ignition 'on' but not engaged. I quickly moved gear back to park and turned off engine. But, not it will not start at all. I checked all fuses and links, and all seems as it should be. However, when I jump relay it just clicks. It seems I cannot jump the starter selenoid either. In addition, the back up lights do not work at all. Any suggestions? Yes, placed full charge on battery. Thanks.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You really shouldn't have battery power hooked up when trying to adjust the NSS. You should use an ohmeter to detect when the NSS makes contact and assure that this only happens in Park and Neutral. You can also use the ohmeter to detect when the back-up light circuit is 'made' (should be in Reverse, only). Don't reconnect the battery until the NSS is operating properly.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
After rewiring my vette, it would not start in park, so I purchased a new neutral safety switch. It worked fine, except the backup lights remained on in every gear (did not happen with old switch). I returned the defective switch for a replacement. Upon installing the replacement, it started in park, however, when I set forth to adjust the position for neutral, it turned the engine over while ignition 'on' but not engaged. I quickly moved gear back to park and turned off engine. But, not it will not start at all. I checked all fuses and links, and all seems as it should be. However, when I jump relay it just clicks. It seems I cannot jump the starter selenoid either. In addition, the back up lights do not work at all. Any suggestions? Yes, placed full charge on battery. Thanks.
Thread Starter
5th Gear
Joined: Jun 2011
Posts: 5
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Thanks Bob. It is a 74 with 350 and automatic. This is the second swittch I installed with problems. However, only found one vendor who carried item. Original switch worked with exception of park, so rewire was ok. I am going to check ignition switch as you suggested. Thanks again.
Safety Car
Joined: Oct 2007
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From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
a switch, is a switch, it does not care about park position.
you need to test each switch with an ohm-meter to verify it works properly.
after that it is either your wiring, or a mechanical position setup of the switch.
get a basic ohm-meter, and learn to use it.
you need to test each switch with an ohm-meter to verify it works properly.
after that it is either your wiring, or a mechanical position setup of the switch.
get a basic ohm-meter, and learn to use it.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Thanks Bob. It is a 74 with 350 and automatic. This is the second swittch I installed with problems. However, only found one vendor who carried item. Original switch worked with exception of park, so rewire was ok. I am going to check ignition switch as you suggested. Thanks again.
you could also use a 12volt test light to one of the two leads and see
what happens when you turn the ignition switch, one will be hot in the crank position only and the other should never be hot
Thread Starter
5th Gear
Joined: Jun 2011
Posts: 5
Likes: 0
Thanks. I have reinstalled old switch and tested with light. The ignition 'surge' current is coming through, but still no ignition. I even took out starter to bench test and make sure solenoid on starter ok. All good. A bit of a mystery. I checked ignition switch and all test ok. Running out of options in the ignition line, but will keep checking. Traced current all the way through. Starter relay was replaced already, but should be irrelevant as I tried shorting across poles to bypass with no success. As to other response...ohm meter...what's that..HA!
Race Director
Joined: Mar 2006
Posts: 14,112
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From: Florida
Make sure you bypassed the proper wires at the relay.
Here is a simple permanent bypass.
The complete circuit is pretty simple,
ignition start terminal>neutral switch>start relay> purple wire on solenoid.
On original neutral switches, I have soldered the crimped oem connections and solved start wire issues, but be carefull not to melt the plastic.
Here is a simple permanent bypass.
The complete circuit is pretty simple,
ignition start terminal>neutral switch>start relay> purple wire on solenoid.
On original neutral switches, I have soldered the crimped oem connections and solved start wire issues, but be carefull not to melt the plastic.
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Race Director
Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
interesting...about the only thats left is a bad ground for the starter. you said you traced the line to the starter so that when you turn the ignition switch to crank you are seeing 12 volts at the solenoid? if so clean all the grounds that go from the engine to the frame horn by the fuel pump. perhaps you have a ground that is just good enough for a volt meter or a test light but will not support the high draw of the cranking starter. does you starter have a ground bracket at the end towards the front of the car that mounts to the engine? if so clean all of those areas.
edit: i think you should clean all your grounds especially from the battery to the frame and also make sure your battery is fully charged
edit: i think you should clean all your grounds especially from the battery to the frame and also make sure your battery is fully charged
Last edited by bobs77vet; Jun 21, 2011 at 09:38 PM.
Advanced
Joined: Aug 2008
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I've had same problems before. First thing I did was to rebuild my auto tranny, because I thought it was that which made the noise. Well, it actually was my starter that was cranking in Drive....
My solution:
Cut the purple short wire going from one contact to the other on the NSS. I think 74-75 have this wire, but I don't know why its there. But it worked for me.
http://www.zip-corvette.com/ProductD...GR-SR&CTitle=&
Good luck
My solution:
Cut the purple short wire going from one contact to the other on the NSS. I think 74-75 have this wire, but I don't know why its there. But it worked for me.
http://www.zip-corvette.com/ProductD...GR-SR&CTitle=&
Good luck
Last edited by kiretunk; Jun 23, 2011 at 04:36 PM.
