Electrical Gremlin

[BigBlue]

Hey guys. I have a little bit of an issue, wanted to see if anyone has had this experience:

A month ago, I tried cranking the car to take it out for a spin, and it just stayed silent. It wouldn't click or anything. All the accessory lights turn on, everything else works, but no crank. I changed the ignition switch and starter solenoid. Still nothing. However, when I turn the key to the ON position, go to the front of the car and bypass the solenoid with a screwdriver, the car cranks up fine and runs perfectly. But it won't turn on with the key. I can even have it running and turn the key to OFF and it'll turn off. But no starting from the cabin. I checked the fuses and as much wiring as I could, but have found nothing wrong. I tested the ignition switch (in case it's a dud) but it checks out fine. The neutral safety switch has been disconnected for ages and it has always run perfectly, so I don't think that would be the problem (but who knows). The car has an old alarm system, so that might be an issue. Or maybe some damaged wire somewhere under the dash that I can't see. I'm about to give up and call an electrician. Has anyone had this problem? HELLPPPPPP!!!!

 

[midlife]

Check your jumper on the NSS signal: sounds like it came disconnected.

 

[Blueoval71]

Crap almighty I just typed out two long paragraphs and deleted it on accident. Here's a short version. If you have a test light or meter this should be straightforward. If you do not just pick up a cheap one form a hardware or auto parts store. I normally do not use a test light, but you shouldn't be able to wound anything by using it. Be sure that the meter or test light has a SOLID ground at each point you test. Disconnect the red w/Blue stripe wire (starter) from the solenoid. Verify that the wire does not have voltage while cranking. Based on what you reported it should not. The next place to check is the actual ignition harness output on top of the steering column. Hopefully you are Hobbit sized or bendy. Check the red w/blue stripe wire coming out of the column. If you get power while in the start position there is a interruption inline. If you do not get power the contacts may be oxidized or the plunger may not be moving far enough. If you are comfortable doing so you can try introducing power directly into the wire to see if the solenoid fires (remember to reconnect the wire to the solenoid). If you are nervous about doing this pull the wire off the side of the solenoid that goes to the starter itself (large gauge). That way you'll just get the "clunk" from the solenoid. Again if you did get power coming from the column it will be interrupted inline. Likely places to check are the firewall connector and neutral safety switch. If there are remains of an alarm look for a relay inline on the starter wire and eliminate it.

Good luck!

 

[JimNiki]

that's what I love about our old cars. No computers to complicate issues. It's as simple as "the thigh bone is connected to the knee bone" etc. Follow the solenoid wire from the ignition. Check if it lets 12v through. Next check as others have said, the nss. Bypass if you have to for the sake of the test. Don't trust your eyes or make assumptions, a multimeter doesn't lie. It's usually almost always something simple.

 

[Blueoval71]

Yes more of an electrical Mogwai than Gremlin.

 

[marks73]

Follow the path Luke!

http://www.7173mustangs.com/images/1971_full.pdf

 

[BigBlue]

Thank you for the replies, gentlemen. Going to check this afternoon, hopefully I'll find something.

 

[Chris Womack]

I had similar problems too -- I ran another wire from ignition switch to starter solenoid (because my red wire/blue stripe was shorted under the dash).

 

[Jim and Jutta]

...The car has an old alarm system, so that might be an issue...

If the alarm system is the type wired into the ignition system it very well may be the gremlin, the alarm system may have figured it's time to retire and shut everything down.

Jim

 

[BigBlue]

Today I got a chance to check the car. I tested the ignition switch, which checked out fine. Then I followed the red/blue wire to the fuse box, which still registered full voltage in the start position. I followed the wire through the firewall, which gave me full voltage the whole time. It came to a dead end right at the neutral safety switch. The C4 has no NSS, so the plug was hanging from the harness. I bypassed it and the car started right up. Problem solved. Now I'm wondering how it started for years without a NSS. I guess some mysteries may never be solved.

Thanks to everyone for all the help!

Crap almighty I just typed out two long paragraphs and deleted it on accident. Here's a short version. If you have a test light or meter this should be straightforward. If you do not just pick up a cheap one form a hardware or auto parts store. I normally do not use a test light, but you shouldn't be able to wound anything by using it. Be sure that the meter or test light has a SOLID ground at each point you test. Disconnect the red w/Blue stripe wire (starter) from the solenoid. Verify that the wire does not have voltage while cranking. Based on what you reported it should not. The next place to check is the actual ignition harness output on top of the steering column. Hopefully you are Hobbit sized or bendy. Check the red w/blue stripe wire coming out of the column. If you get power while in the start position there is a interruption inline. If you do not get power the contacts may be oxidized or the plunger may not be moving far enough. If you are comfortable doing so you can try introducing power directly into the wire to see if the solenoid fires (remember to reconnect the wire to the solenoid). If you are nervous about doing this pull the wire off the side of the solenoid that goes to the starter itself (large gauge). That way you'll just get the "clunk" from the solenoid. Again if you did get power coming from the column it will be interrupted inline. Likely places to check are the firewall connector and neutral safety switch. If there are remains of an alarm look for a relay inline on the starter wire and eliminate it.

Good luck!

Right you were! There was an interruption in the line in the form of a neutral safety switch. It wasn't even plugged. The transmission doesn't have a NSS, so the plug was just there, hangin' out. Once I bypassed it, it cranked right up, no issues. What's boggling my mind now is how the hell I managed to drive it for years with no NSS connection and never had a problem with starting it. But at this point I don't care, I'm just happy it starts again.

Thanks a million for the great advice... another Mustang back on the road!

Check your jumper on the NSS signal: sounds like it came disconnected.

That's exactly what it was! No NSS at all, just a plug in the air. A quick bypass and everything's back to normal. Thanks!!!!

 

[JimNiki]

the spirit of "Christine" has finally left your vehicle...

 

[BigBlue]

the spirit of "Christine" has finally left your vehicle...

Wouldn't be the first time lol. Many years ago, I had left the car without washing for a couple of months and it was filthy. One afternoon, I try to crank it and it wouldn't start. I had driven it earlier, so I was confused. I try to start it up a few times, to no luck. After about 5 or 6 tries, I barter with the car. "Ok Blue, I promise if you start I'll wash you this weekend". Started right up. Didn't have any more starting issues after that. That's one of the many weird stories I have about the car. I think I should open a thread about "Christine" moments. I'm sure I'm not the only one that's experienced it.

 

[midlife]

Today I got a chance to check the car. I tested the ignition switch, which checked out fine. Then I followed the red/blue wire to the fuse box, which still registered full voltage in the start position. I followed the wire through the firewall, which gave me full voltage the whole time. It came to a dead end right at the neutral safety switch. The C4 has no NSS, so the plug was hanging from the harness. I bypassed it and the car started right up. Problem solved. Now I'm wondering how it started for years without a NSS. I guess some mysteries may never be solved.

Thanks to everyone for all the help!

Crap almighty I just typed out two long paragraphs and deleted it on accident. Here's a short version. If you have a test light or meter this should be straightforward. If you do not just pick up a cheap one form a hardware or auto parts store. I normally do not use a test light, but you shouldn't be able to wound anything by using it. Be sure that the meter or test light has a SOLID ground at each point you test. Disconnect the red w/Blue stripe wire (starter) from the solenoid. Verify that the wire does not have voltage while cranking. Based on what you reported it should not. The next place to check is the actual ignition harness output on top of the steering column. Hopefully you are Hobbit sized or bendy. Check the red w/blue stripe wire coming out of the column. If you get power while in the start position there is a interruption inline. If you do not get power the contacts may be oxidized or the plunger may not be moving far enough. If you are comfortable doing so you can try introducing power directly into the wire to see if the solenoid fires (remember to reconnect the wire to the solenoid). If you are nervous about doing this pull the wire off the side of the solenoid that goes to the starter itself (large gauge). That way you'll just get the "clunk" from the solenoid. Again if you did get power coming from the column it will be interrupted inline. Likely places to check are the firewall connector and neutral safety switch. If there are remains of an alarm look for a relay inline on the starter wire and eliminate it.

Good luck!

Right you were! There was an interruption in the line in the form of a neutral safety switch. It wasn't even plugged. The transmission doesn't have a NSS, so the plug was just there, hangin' out. Once I bypassed it, it cranked right up, no issues. What's boggling my mind now is how the hell I managed to drive it for years with no NSS connection and never had a problem with starting it. But at this point I don't care, I'm just happy it starts again.

Thanks a million for the great advice... another Mustang back on the road!

Check your jumper on the NSS signal: sounds like it came disconnected.

That's exactly what it was! No NSS at all, just a plug in the air. A quick bypass and everything's back to normal. Thanks!!!!

Damn, I'm good. That's one out of 2,049,103 responses.:s

Beats me why it started before...