# 68 electical issue



## Matthew (Feb 11, 2011)

Looking for some counsel, or humor as I have had a couple good laughs reading your posts for several months. I suspect a bad ignition switch, but certainly open for suggestions. The car is a 68, manual trans, no a/c. With the ignition switch in the ON position, all lights and accessories work as normal. In the START position, I get nothing -- no draw on the battery and no sound at the solenoid. The battery is good and the cables are new with solid and connections. Bench tested the starter and it is good as well. Connections at the starter are good. Light tested the switch to solenoid (purple) wire in START position – have not put an Amp meter on it. Put an Ohm meter on the solenoid wire from the firewall connection to the starter connection – no resistance. Grounds all seem to be good – battery to engine and engine to chassis and frame. Even ran a separate ground from the starter to the frame.

I had no early indications of a problem. Everything was working fine up to the failure. The engine wire harness is about 4 months old. Both leads to the starter (purple and red) coming from the harness are in good condition. The only other recent activity with the electrical system was to remove the AM radio and front speaker. Simply unplugged the components and removed them. I have not installed the replacements yet.

Now, I would have already replaced the ignition switch and confirmed it was or was not the problem, but the little fellows are hard to find. Thanks in advance for any ideas you might have. Matt


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## Rukee (Feb 8, 2007)

So, when you tested the purple wire at the starter in the start poss, did it have power??
If not, does your car have a clutch safety switch?? If so, is the power going through both sides with the key in the start poss??


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## Matthew (Feb 11, 2011)

Yes sir. With a test light, I had power at the solenoid "S" terminal with ignition switch in the START position. I did not check for the level of power. 

I also looked for clutch safety switch and I could not find one. I have to assume I don't have one, otherwise I would not get a positive test at the solenoid. More thoughts? Thanks, Matt


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## freethinker (Nov 14, 2009)

jump the solenoid s terminal to the batt terminal on the solenoid to eliminate the battery circuit. if it cranks you have a problem with the power wire from the starter through the ignition switch,back to the starter. could be at the fuse block where it passes through the firewall or a terminal on the switch or the switch itself. eliminate possibilities one at a time.
radio would have no effect.


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## Rukee (Feb 8, 2007)

If you have 12+ at the S terminal it should be cranking. I would also like freethinker suggest, jump the s terminal to the battery cable post and see if you get any action. Be sure the car's rear tires are off the ground or at least be sure your in neutral!!.


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## Matthew (Feb 11, 2011)

I will follow up on your thoughts here. I should have check the voltage at the S terminal rather than a test light. Had assumed if I had any juice, I would at least get a clicking -- I've got nothing. I also assumed the only way to have lights, gauges and accessories was to have connectivity through the power wire (red) coming from the starter to the alternator (red and black) and into the terminal connector at the fire wall.

Based on your suggestions, I will drop the starter to get at the terminal connections, check voltage at both the battery and S terminals, then establish a ground for the dangling (supported) starter and jump across the two. Got the safety piece down cold. Will let you know what I find out. Thanks again, Matt


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## BearGFR (Aug 25, 2008)

I don't remember - does a 68 have the interlock that prevents the starter from engaging unless the trans is in neutral? If it does, suspect that. Or if the steering column perhance has been changed out for one that has that feature. What you describe is exactly how my 69 acts if the interlock lever on my steering column that links to the transmission (auto) isn't in exactly the right position.

Bear


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## Eric Animal (Oct 28, 2007)

I think interlock BS started in 1969. I bet its a poor ground, or bad starter. E


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## freethinker (Nov 14, 2009)

Matthew said:


> I will follow up on your thoughts here. I should have check the voltage at the S terminal rather than a test light. Had assumed if I had any juice, I would at least get a clicking -- I've got nothing. I also assumed the only way to have lights, gauges and accessories was to have connectivity through the power wire (red) coming from the starter to the alternator (red and black) and into the terminal connector at the fire wall.
> 
> Based on your suggestions, I will drop the starter to get at the terminal connections, check voltage at both the battery and S terminals, then establish a ground for the dangling (supported) starter and jump across the two. Got the safety piece down cold. Will let you know what I find out. Thanks again, Matt


i would try and jump it on the car. with stock,non ram air, manifolds its possible. take a long screw driver and tape up the blade, for insulation, except for about 1 inch on the bottom. then looking down where the battery cable goes over the manifold you can see the battery terminal on the solenoid. slide the screw driver down to touch that and the inner terminal on the solenoid.


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## Matthew (Feb 11, 2011)

I rechecked for a clutch safety switch -- if I have one, the little fellow is well hidden. Mr Eric is correct about the 69 vs 68. That said, it sure seems like a circuit interruption similar to a nuetral safety. Mr Bear, I looked around the transmission (manual) and the only electrical connection is the back up light switch. OK, I did as Mr Freethinker suggested -- jumped across the solenoid battery terminal and the S terminal. The starter engaged as it should. I believe this tells me I have a good battery connection and a solid ground at the starter. I can't do a voltage check on the S terminal as Mr Ruckee suggests without dropping the starter. Will have to do that tomorrow evening. Thanks for the counsel. Matt


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## freethinker (Nov 14, 2009)

Matthew said:


> I rechecked for a clutch safety switch -- if I have one, the little fellow is well hidden. Mr Eric is correct about the 69 vs 68. That said, it sure seems like a circuit interruption similar to a nuetral safety. Mr Bear, I looked around the transmission (manual) and the only electrical connection is the back up light switch. OK, I did as Mr Freethinker suggested -- jumped across the solenoid battery terminal and the S terminal. The starter engaged as it should. I believe this tells me I have a good battery connection and a solid ground at the starter. I can't do a voltage check on the S terminal as Mr Ruckee suggests without dropping the starter. Will have to do that tomorrow evening. Thanks for the counsel. Matt


ok now we have eliminated the battery, starter and the cables. now what i would do is pull the connector off the ignition switch and make myself a u shaped piece of wire and jump the power and the start wire. that will eliminate the ignition switch. if it cranks you have a bad switch. if not you have a wiring problem.


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## Matthew (Feb 11, 2011)

Thank you sir, I will continue to follow up on any and all suggestions. I'm positive there's no nuetral safety switch on my steering column. I don't think I've ever seen a clutch safety switch before, but would guess it would look similar to a brake light switch. Regardless, there's no switch/electrical connections around my clutch compenents internally or externally. 

There are 8 terminal connections on the 68 GTO/Lemans/Tempest ignition switch: KEY+, KEY-, GRD, BAT, ACC, SOL, IGN and IGN 2. Tell me if I'm wrong here, but I believe you are recommending I jump the BAT to SOL briefly. Thanks again, Matt


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## freethinker (Nov 14, 2009)

Matthew said:


> but I believe you are recommending I jump the BAT to SOL briefly. Thanks again, Matt


yes.


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## Matthew (Feb 11, 2011)

Looks like 13.4 volts comining into the ignition switch. The jump from BAT to SOL on the switch connection had no reaction at the starter. So, as you pointed out, the switch is not likely the problem. On to the connection at the fire wall next, as I had previously checked the the solenoid wire from the fire wall connector to the starter. Make sense? Will work this tomorrow evening. Thanks again, Matt


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## freethinker (Nov 14, 2009)

Matthew said:


> Looks like 13.4 volts comining into the ignition switch. The jump from BAT to SOL on the switch connection had no reaction at the starter. So, as you pointed out, the switch is not likely the problem. On to the connection at the fire wall next, as I had previously checked the the solenoid wire from the fire wall connector to the starter. Make sense? Will work this tomorrow evening. Thanks again, Matt


i think you are on the right track.


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## geeteeohguy (Feb 2, 2008)

I think so too. Nothing but good advice, and it sounds like you know what you're doing, Matt. If you don't, at least you're using logic and your brain to narrow it down. Congrats, you'll fix it for sure. As you've found out, a lit test light can give you erroneous readings.....it'll show voltage, but not voltage drop. You may have only one strand of a 30 strand wire making contact, and ti'll light the lamp. But turn the key, and ZIP. I'll bet it's the wire from the switch to the solenoid.


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## Matthew (Feb 11, 2011)

I'm not sure I know what I'm doing, but did work with a couple of real professionals back in the 70s. One of them was a WWII veteran and thought everyone should do their part, so I took a 30 year vacation from this stuff. I appreciate you gentlemen spending a little time with me. OK, not fixed yet, but closer. Will let you know tomorrow evening. Respectfully, Matt


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## Matthew (Feb 11, 2011)

Close out report. The 68 is fully mission capable again. The issue was that I had lost a clean connection of the ignition solenoid (purple) wire at the firewall connector. The engine wire harness firewall connector is, as it should be, packed with dielectric grease. I had installed the harness about four months ago. In trying to isolate the failure, I separated the connection to check resistance on the solenoid wire to the starter - there was no resistance, so I reconnected and moved on.

Since the battery and starter had checked out good, I was convinced the issue was an ignition switch. I would have immediately ordered a new switch and replaced it, but the switch for a 68 is not in production right now (PY says later this year). That said, it would not have fixed my problem. To add to my confusion, I had used a test light at the starter solenoid S terminal with a positive result. No, I did not check with a volt meter like I should have. Mr Geeteeohguy makes a good point in his message. Maybe to most it would be considered a "blinding flash of the obvious." Some know this as well... working with the electrical connections on that starter with a stock exhaust, heat shield and a no slack wire harness in a non-hoist repair environment is pure fun.

OK, so the counsel I received, as you can see from previous posts, was to eliminate the switch as the problem and work back to the starter. The check on voltage coming into the ignition switch showed 13.4v. I then reconnected at the switch and checked voltage at the firewall connector – and to my amazement, all good. I then made a small jumper wire and hooked up on both firewall connectors… there it was, power to the solenoid. OK, so as I mentioned in the beginning, the connector was packed with dielectric grease. While that is a good thing, I was not fully seating the two connectors – gently tightened retainer bolt was simply tightened too gently. 

Thanks for the coaching. I do enjoy many of the unique characters on the forum. And a personal thanks to the ones that shared ideas. Never thought about how Mr Freethinker came to have that name, but I think I know now, given he has no where to send the bill. Respectfully, Matt


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## geeteeohguy (Feb 2, 2008)

Great news. I've been thru the same thing on these cars more than once, Matt. In my case, the last time, it was a bad purple wire about an inch back from the ign. switch. Experience has shown me that about 90% of the time, it's a bad connection/faulty wire as opposed to a bad component. Glad you fixed it!!!!


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