[TedRamAirII]

Continuity with a OHM Meter, doesn't mean squat. You need to check voltage (under a load) in and out of the Ignition Switch while in the Crank Mode. If that passes, then do the same at the Violet Wire and the shifter, Voltage in and then out. Passes that test? suspect the Bulkhead Connection.

[bulletpruf]

Originally Posted by TedRamAirII

Continuity with a OHM Meter, doesn't mean squat. You need to check voltage (under a load) in and out of the Ignition Switch while in the Crank Mode. If that passes, then do the same at the Violet Wire and the shifter, Voltage in and then out. Passes that test? suspect the Bulkhead Connection.

If you'll scroll down, you'll see that I already checked the voltage - under a load - on the purple wire at the NSS - input and output.

What wire do I use to check the voltage going in the switch?

[Shiny]

I found a dash diagram for 68 on this website:

https://www.gtoforum.com/threads/ele...m-scans.22042/

Assuming this is correct, the switch should be fed with a red wire:



You should measure battery voltage or just a little less at that terminal on the switch when the starter is activated and the solenoid is loading the circuit.

You measured only 7.X V at the NSS.

This suggested there was a high resistance between the battery and the NSS switch.

If that high resistance is the switch itself, you will measure ~12V at the red contact and 7.X V at the switch contact feeding the NSS (purple wire, labeled SOL on the diagram). If this happens, replace the switch. If you measure 12V at the red contact and 12V at the purple contact, the high resistance is in the purple wire or a connector between the switch and the NSS.

[bulletpruf]

Thanks for the explanation and diagram, Mike!

I got the switch back together and installed and tried it again just now. No joy.

Now 'm getting 8 - 8.5 volts at the NSS. I bypassed the NSS with a jumper wire just to take it out of the equation and still no luck.

Battery is at 12.1 volts now, so I'm charging it up. Next step will be to check voltage under load at the switch.

Thanks again,

Scott

[bulletpruf]

Ok, I think I have it figured out - it's the ignition switch.

I got 12.5 v to the input (red wire) going in to the ignition switch. Under load, it dropped to 11.5 v. On the purple wire going to the NSS (output) I only got 8.5 v as I had the key turned to the "start" position. The first two times I turned the key to start, the starter engaged and engine turned over, but nothing after that.

I'll get an ignition switch on order and get it all put back together. I'll let y'all know once it's all back together and working fine.

Thanks again for all the input!

[Greg Reid]

Verify that it's the switch and not a partial short or high resistance in the output somewhere by a jumper across the switch. That would take the switch itself out of the equation. That is, jump from the red wire on the input of the switch to the purple wire on the output of the switch.

[Shiny]

What Greg said.

You just cleaned the contacts on the ignition switch so seems less likely to be bad than a wire or connector.

You may not have eliminated the possibility of a bad wire between the ignition switch and the NSS. By "bad wire", it could be corrosion where the connector terminals are crimped onto that wire. The wires themselves can also corrode if the insulation breaks down or got torn. And like Greg suggests, the purple wire could have a short somewhere. The diagram shows a solid wire between the ignition and NS switches, reducing some complexity if bulkhead connections were involved.

[bulletpruf]

Damn. Just as I was getting ready to take my victory lap, y'all rained on my parade...

Of course, what y'all are saying makes a lot of sense, so I guess I have another task to accomplish.

[bulletpruf]

How can I remove the wires from the plug going into the ignition switch to inspect them? Figure if I can pull the red and the purple wires that would be worth my while to inspect.

Thanks

[BB70]

If you look at the connector end that goes to the switch, where the opening of the terminals are, there are little squares in the center of each terminal opening. Get a little ground down pick or screwdiver and stick it in till it bottoms out. That should depress the release . You may have to push in on the wire to get a clean release and maybe lift on your tool to. When you reinstall the wire make sure you bend back up the lock tab on the terminal so the wire stays in the connector

[bulletpruf]

Originally Posted by BB70

If you look at the connector end that goes to the switch, where the opening of the terminals are, there are little squares in the center of each terminal opening. Get a little ground down pick or screwdiver and stick it in till it bottoms out. That should depress the release . You may have to push in on the wire to get a clean release and maybe lift on your tool to. When you reinstall the wire make sure you bend back up the lock tab on the terminal so the wire stays in the connector

Thanks, I'll give that a shot.

Scott

[BB70]

If it doesn't make sense, put a picture of the connector up.

[bulletpruf]

Originally Posted by BB70

If it doesn't make sense, put a picture of the connector up.

That makes sense. I'll give it a shot at some point in the next few days when I can break free from work.

Thanks

[BB70]

Man, I think I might have steered you wrong, I thought you had a 69, but you have a 68. I don't know if they come apart the same or not.

[Greg Reid]

Did you jumper the red wire to the purple wire across the switch?

[72LuxuryLeMansLa.]

Originally Posted by Jim Scites

Have you tried starting it in Neutral instead of park? If the shifter is out of alignment and the neutral safety switch is not making a good connection, trying to start it in neutral might prove it. Foot on the brake and parking brake applied Put the car in neutral and if it doesn't start try wiggling the shifter and see if it starts. Also you might try a temporary jumper wire across the neutral safety switch connection.

Jim,


I call this my anti-theft feature. My 72 Luxury LeMans refused to start years ago. I looked at the scematic and placed the car in neutral. It started. I have since done it that way and intend to keep it as an anti-theft feature. It works the same way as a standard transmission. Young idiots can't figure it out so they can't steal it.


As to the original post; follow Shiny and George. Split the circuit, find which half is bad, split it again until you find the culprit.

[bulletpruf]

Originally Posted by Greg Reid

Did you jumper the red wire to the purple wire across the switch?

Not yet. Will try one morning before work later this week.

[TedRamAirII]

Originally Posted by bulletpruf

If you'll scroll down, you'll see that I already checked the voltage - under a load - on the purple wire at the NSS - input and output.

What wire do I use to check the voltage going in the switch?

Sorry I didnt go back that far. You say it lost 1 volt under load at the Red wire at the switch, thats not good. You dont want any voltage loss. You want a full 12V at the purple wire, A good charged battery has 12.6V. Use your Volt Meter to find where its losing voltage. Under cranking of course you may lose 1. -1.5 volts. But you need to be sure everything is as good as it can be. Do the same for ground too. Measure from body to the battery negative, and Engine to the Negative under cranking load.

[NeighborsComplaint]

Originally Posted by bulletpruf

Ok, I think I have it figured out - it's the ignition switch.

I got 12.5 v to the input (red wire) going in to the ignition switch. Under load, it dropped to 11.5 v. On the purple wire going to the NSS (output) I only got 8.5 v as I had the key turned to the "start" position. The first two times I turned the key to start, the starter engaged and engine turned over, but nothing after that.

I'll get an ignition switch on order and get it all put back together. I'll let y'all know once it's all back together and working fine.

Thanks again for all the input!

See Post #28. I tried to save you a lot of unnecessary troubleshooting. The chattering solenoid says all is working just not enough voltage due to poor contact/high resistance or a weak battery.

[bulletpruf]

Originally Posted by TedRamAirII

Sorry I didnt go back that far. You say it lost 1 volt under load at the Red wire at the switch, thats not good. You dont want any voltage loss. You want a full 12V at the purple wire, A good charged battery has 12.6V. Use your Volt Meter to find where its losing voltage. Under cranking of course you may lose 1. -1.5 volts. But you need to be sure everything is as good as it can be. Do the same for ground too. Measure from body to the battery negative, and Engine to the Negative under cranking load.

Ok, thanks.