Neutral Safety Switch

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moparspares

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I am having trouble with my NSS. I had nothing when turning key. Disconnected wiring at switch and then It turned over. Removed harness and checked connections and everything fine. Plugged it all back in and nothing. I suspect the problem is further down the line in the column. Any ideas?.

PS Car now has B&M shifter and instructions say use the original NSS and disregard the micro switch on the shifter
 
I never know how much the person asking the question knows. Plus when you say you disconnected the wire from the switch, I don't know what that means. I can guess, but what switch are you talking about, so here goes. The neutral safety switch (NSS) in the tranny completes a ground when the tranny is in neutral or park. There is a wire going from the inner fender mounted starter relay (left side behind the battery) down to the NSS. Another one of the wires going to the relay is from the ignition switch. When the ignition switch is turned to the start position, current flows through the ignition switch wire to the relay, through the relay, and down through the wire that goes to the NSS. If tranny is in park of neutral, a ground is completed and the current is allowed to flow through the relay to a ground. That activates an electromagnet in the starter relay that completes another circuit that allows current to flow through a wire from the relay to the starter solenoid. Then, assuming you have a good starter, the starter will turn over.
First, check to see if you have current at the relay in the wire coming from the ignition switch when the ignition switch is turned to the start position. Then check for current at the relay in the wire going down to the NSS when the ignition switch is turned to the start position. If both of these current tests are good, you likely have a bad NSS. Using a jumper wire, ground out the relay terminal that has the wire going to the NSS. That will simulate a NSS that works and allow current to flow through the relay to the starter solenoid.
 
Typical ign' switch to relay is yellow wire, hot in start. Typical relay to NSS switch is brown wire. Typical service manual states adjust shifter to trans lever(s) while both centered in neutral positions. So IF you just changed the shifter, adjustment may be the only problem. Hope this helps
 
1 thing not to overlook is to have a ground strap from engine to body with clean connections. Most of the cars we have today have have a few owners and who knows what was left OFF.
 
"Pretty much" what harrisonm and Redfish said!!!!!!

the idea that it would crank with the switch disconnected is TROUBLING. Either you are mistaken, or there might be a bare wire leading to the NSS which became grounded and allowed the relay to energise. This is dangerous because the engine could then start "in any gear."
 
Agreed. The starter relay shouldn't actuate if the NSS is disconnected, since that is "open circuit" and the NSS should be open in any gear but P or N, to disable the relay. Sounds like you have a manual transmission. I have never worked on those, so don't know if the NSS is on the downstream side (like automatics) or upstream, but the wiring schematic will tell you.
 
Agreed. The starter relay shouldn't actuate if the NSS is disconnected, since that is "open circuit" and the NSS should be open in any gear but P or N, to disable the relay. Sounds like you have a manual transmission. I have never worked on those, so don't know if the NSS is on the downstream side (like automatics) or upstream, but the wiring schematic will tell you.
Says he has a B&M shifter in post 1. So must be an auto.
 
Says he has a B&M shifter in post 1. So must be an auto.
OK. Not familiar with those. I ASSumed any custom shifter would be for a manual, since finesse can matter there. For auto transmissions, a rotary knob like new cars suffices, or the push-buttons in my 64 Valiant. My 65 Dart is auto (cable-shift) w/ a floor shifter. That must have been just to impress the babes with your manliness, though hinders attempts at intimacy.
 
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