Won't Start in Park or Neutral

[money pit]

My car (74 360, 727 trans) won't start in park or neutral. I replaced the neutral safety switch and adjusted the shift linkage (slap stick) per service manual. That didn't seem to work. I replaced the starter relay, that didn't work. If I jump the terminals at the starter relay with the ignition on, it will start. I was reading on a thread that said there should be 12 V to the yellow wire on the starter relay and if you ground the brown wire on the relay and the car starts, there's a problem with the wiring or NSS. Is there a way to test the wiring to the neutral safety switch? I know there are 3 terminals on the NSS. What goes to these terminals, power, ground, back up lights? I noticed that if I jump start the starter relay and drive the car, the car will sometimes start with the ignition key. Any thoughts? Thanks.

 

[DetMatt1]

Sounds like it could be your ignition switch.

 

[rklein71]

You can remove the ground wire from the starter relay (this wire goes to your neutral safety switch) and do a temporary ground wire from the starter relay to the chassis. This will bypass the neutral safety switch so you can see if the car will start.

 

[money pit]

Sounds like it could be your ignition switch.

I'm going to check the connections. I removed the steering column when I replaced the steering gear. Thanks

 

[money pit]

You can remove the ground wire from the starter relay (this wire goes to your neutral safety switch) and do a temporary ground wire from the starter relay to the chassis. This will bypass the neutral safety switch so you can see if the car will start.

I'll try that. Thanks

 

[rklein71]

If it won’t start with the temporary ground, check to if you are getting 12 volts to the starter relay. If you are getting 12 volts, relay is bad. No voltage, ignition switch most likely cause. Although you could have a break in the wire from the switch to the relay.

 

[money pit]

If it won’t start with the temporary ground, check to if you are getting 12 volts to the starter relay. If you are getting 12 volts, relay is bad. No voltage, ignition switch most likely cause. Although you could have a break in the wire from the switch to the relay.

This is what I found so far. I get power to the yellow wire on the starter relay. I grounded the terminal on the starter relay (where the brown wire connects) and I'm able to start the car with the key. I checked the wire to the NSS. The center connector has continuity with the brown wire on the starter relay. The two outer connectors have continuity with the connectors on the fire wall. I pretty sure it's the NSS, even though I just replaced it. Any recommendations? Thanks

 

[rklein71]

Just curious, do your back up lights work?

 

[rklein71]

You could pull your NSS off the transmission and check for switch operation with a multi-meter.

 

[Mopars & Missiles]

That little 3 wire harness from the NSS to the relay can be bad also. I had an intermittent in the ground wire (center wire) on one of my cars several years ago. Replaced the 3 wire harness, perfect ever since. Nothing wrong with the NSS.

 

[72RoadRunnerGTX]

Verify the center terminal on the NSS is going to ground in park and reverse only and is open in all other gears. If not, it’s a switch problem or alignment issue with the switch, be sure there is only one gasket/seal under the switch. The two outer terminals are the reverse light switch, should be closed to each other in reverse, open in all other gears.

 

[money pit]

Just curious, do your back up lights work?

No back up lights.

 

[money pit]

That little 3 wire harness from the NSS to the relay can be bad also. I had an intermittent in the ground wire (center wire) on one of my cars several years ago. Replaced the 3 wire harness, perfect ever since. Nothing wrong with the NSS.

I checked the wiring, it seems to be okay. I was going to change it anyway since its pretty brittle. Thanks

 

[Mopars & Missiles]

..... I get power to the yellow wire on the starter relay........... I grounded the terminal on the starter relay (where the brown wire connects) and I'm able to start the car with the key..............

This statement proves where your problem is. Its in the "ground circuit" to the starter relay. This can ONLY be a couple of possibilities.

1. The NSS switch is "BAD".
2. The 3 wire harness from NSS to relay is "BAD". (can be intermittent and hard to verify)
3. The shift linkage is not adjusted properly. ("BAD")
4. The "rooster comb" is not providing a ground to the NSS. ("BAD")

That's about all that it can be, AFAIK.

 

[72RoadRunnerGTX]

And/or the common inadvertent “doubling-up” of switch seal rings/washers can also prevent a good switch from working as designed. Really need to perform some continuity tests at the switch terminals from the sounds of it.

 

[rklein71]

No back up lights.

Interesting, could be an issue with the NSS switch itself not getting the ball plunged enough to operate the switch.

 

[money pit]

This statement proves where your problem is. Its in the "ground circuit" to the starter relay. This can ONLY be a couple of possibilities.

1. The NSS switch is "BAD".
2. The 3 wire harness from NSS to relay is "BAD". (can be intermittent and hard to verify)
3. The shift linkage is not adjusted properly. ("BAD")
4. The "rooster comb" is not providing a ground to the NSS. ("BAD")

That's about all that it can be, AFAIK.

I agree with your assessment. The only thing I didn't check was the rooster comb. I was avoiding pulling the pan. Thanks

 

[money pit]

And/or the common inadvertent “doubling-up” of switch seal rings/washers can also prevent a good switch from working as designed. Really need to perform some continuity tests at the switch terminals from the sounds of it.

When the plunger is depressed, I should get a ground signal to the center terminal, correct? And when the plunger is extended, I should get a signal to the outer terminals? I don't have the switch out so I'm not sure of the switch positions. Thanks

 

[72RoadRunnerGTX]

With the switch installed, the center terminal should show continuity to ground only in park & reverse, open all other gear selections. The two outer terminals will have continuity to each other only in reverse, no continuity in any other gear and no continuity to ground or the center terminal under any circumstances.

 

[money pit]

And/or the common inadvertent “doubling-up” of switch seal rings/washers can also prevent a good switch from working as designed. Really need to perform some continuity tests at the switch terminals from the sounds of it.

Which way is the rubber seal installed. The photo on the left is the way the NSS was packaged. The second photo seems like the way the seal should be installed.