65 power failure

[JohnZ]

If you end up needing a headlight switch, get it from LICS or one of the other Corvette parts houses; most of the "replacements" from NAPA, etc. are a "universal" design - the connector will fit, but it will leave your front parking lights on with the headlights on, which didn't happen on Corvettes until '68 or '69.

 

[kpauley]

OK, I worked on it a little today, my father in law comes by tomorrow and I'll spend more time on it.

Had started tested (I was checking all the wires there so I figured it couldn't hurt to check it out), it's fine. I replaced the headlight switch. Found a couple more wires that didn't look real great and fixed them, nothing noteworthy.

Interior lights still flicker a lot. The kick panel lights are real sensitive, you move those around and they all flicker a bit.

I'm still going towards the lighting circuit as an issue. Even with the new light switch, as soon as you pull it on, all the power goes out.

I also noticed when I was under the dash that up above the drivers side kick panel there is a circuit breaker. I'm guessing this is what is killing the power and it eventually comes back on after it resets. Could the breaker be the issue? Any way to reset the breaker faster. I suppose I could bypass the breaker and see where the sparks and flames start first to find the problem

Ken

 

[WayneC]

More food for thought......

>>>> You said:

I'm still going towards the lighting circuit as an issue. Even with the new light switch, as soon as you pull it on, all the power goes out.

I also noticed when I was under the dash that up above the drivers side kick panel there is a circuit breaker. I'm guessing this is what is killing the power and it eventually comes back on after it resets. Could the breaker be the issue? I suppose I could bypass the breaker and see where the sparks and flames start first to find the problem

<<<<<<<<<<<

I would NOT wire around that circuit breaker (I assume you were being facetious).

Is that breaker hot to the touch immediately after the failure?

To cause the failure, do you have to pull the headlight switch knob all the way out, or just to the parking light position?

My car has been apart/inaccessible a long time and I can't remember if the headlights move without the light switch knob being pulled out, or even if you have to keep your finger on the position switch until the headlights are fully open or closed, or just flick the switch to start the process and it proceeds automatically.

Will the headlights go up and down while they are turned off (not illuminated, headlight switch knob fully in)? I'd guess yes. When the headlight switch knob is pulled out, does the failure occur no matter whether the headlights are up or down at the time? Will working the headlight positioning switch itself, with headlight switch knob left in, cause the failure? My guess is no, meaning the failure is associated with exterior lighting, not the headlight motors.

From the diagram, it looks like the circuit breaker is inline with the headlight position switch only (ie, the toggle switch that raises and lowers the headlights, not the switch that turns them on) so it seems to me that it is intended to protect that headlight positioning circuit and that it isn't grounded when the position switch is in the neutral position (ie, should not be carrying a load). What do you think?

Or am I looking at the wrong circuit breaker? ...There seem to be two circuit breakers listed in the parts book for 63-65 Corvettes (both in the lighting circuit), although I haven't yet found the second one on the diagram, but I may be reading the parts book incorrectly and one part is actually the switch.

You may be able to simply disconnect the leads to that circuit breaker and see if:

1. the headlights now will not raise or lower (I expect they won't)

2. the interior lights are on but still go out (failure) when you pull out the headlight knob.

If the interior lights aren't going on at all, then the circuit breaker does more than protect the headlight motors; but I doubt it, I expect the interior lights will go on.

If the interior lights now stay on (ie, no failure), then you may have narrowed the search, probably to a bad headlight position switch (since I would think it ought not be passing current if it's in the neutral position) or the wire leading from the circuit breaker to the switch. If my memory is faulty and you only have to give the headlight position switch a flick and it goes full open or closed automatically from there, then there could be a fault in the circuits from the position switch to the motors.

BTW, did you ever track down that grounding wire (black with white tracer) that is bolted to the radiator support to ground the headlight circuit?

 

[kpauley]

I found one ground wire on the drivers side of the radiator (I didn't note the exact color, looked to be about 12/14 gauge), about mid-way up the height of the radiator. It looked to be in good shape.

I was only pulling out the light switch and things go off, if I recall it is as soon as it hits the parking brake point, I'll double check. The headlights are in the down position and it still fails (the headlights did used to go on when it was in the down position). I haven't tested recently, but I seem to recall hitting the toggle switch to raise the lights would have a similar effect, hopefully I can test that today....if I can get the power back on....

Ken

 

[JohnZ]

The circuit breaker above the driver's side kickpad is the self-resetting type, and protects the power feed circuit for the headlight up/down switch - both terminals are "hot" all the time with battery power; it's completely independent of any lighting circuits, fuse block, or ignition switch. There will be another identical breaker adjacent to it if the car has power windows.

 

[kpauley]

Well, we found part of the problem tonight, I'm hoping that I am on the home stretch.

My father in law came over and we started testing voltage, not continuity. We were getting 12V at the battery but in many places where we should have 12V we were only getting 4 or 5. Like at the ignition swtich, light switch, etc. We started tracing down a bunch of the circuits to find out where the voltage drop (or grounding) was coming from. It's hard to isolate a lot of those circuits, they are not as independent as I would have thought.

Well, we traced down almost everthing and things seemed to be strange at the fuse panel, firewall connector. We had 12 V at the firwall connector inside the engine compartment when we disconnected the connector, but on the other side in the cabin we were getting low voltage.

We took apart the fuse panel to look under it. The 12 G Red wire coming in from the engine bay had lost part of it's insulation and seemed to be shorting out. When we had the fuse panel seperated from the connector side all of our voltages came up to 12V. So we taped that over for now and put some plastic insulation between the two for now (needs to be replaced later).

I think that was a pretty major find, but it's not quite over. There still seems to be an issue at the ignition switch. We took the switch out and hooked up jumper wires between the switch and the connector so we could measure the voltage coming off the switch. We hooked up just the BAT lead to the switch. Now when we tested the switch with a meter and nothing connected it seemed right. When you turned the switch on you get continuity from the BAT connector to the ACC and the IGN terminals. Then when you turn to Start, you get continuity to the SOL terminal (I think I am remembering that correctly). We then we gave 12V power to the battery terminal (nothing else connected to the switch) and when you turn it on or to start you get 12V out at each of the correct terminals.

Once we plug the SOL, ACC, or IGN terminals in (with the jumper wires, at any given time only the BAT connection or one of the other ones was hooked up) the voltage coming out of that terminal is between 4 and 9 V, major drop off. Seems like there is something else going on (of course!).

So, I'll try to get out there again, I'm not done with that fuse panel I think, we'll see.

 

[WayneC]

>>>>
We had 12 V at the firwall connector inside the engine compartment when we disconnected the connector, but on the other side in the cabin we were getting low voltage.

...snip...

Once we plug the SOL, ACC, or IGN terminals in (with the jumper wires, at any given time only the BAT connection or one of the other ones was hooked up) the voltage coming out of that terminal is between 4 and 9 V, major drop off. Seems like there is something else going on (of course!)
<<<<

More of my ramblings:

Firewall connector keeps sounding more promising. Did you mean to say "...BAT connection AND one of the other...", because I think BAT should always be hot, as should the red or orange wires to the HEADLIGHT SWITCH, the cigarette lighter, the stop light switch, glovebox light, and door courtesy lights. And, did you mean the voltage between the red wire and one of the other wires varied when connected?

The ignition switch and the headlight switch may both just be reflecting what's happening upstream as the 12gauge red wire goes through the firewall connector, since they are both fed by that same circuit! If that connection is weak, turning either on will try to draw more power through that poor connection. Does the problem occur with the ign sw off when you pull the hdlight sw knob? You should try wiring around the firewall connector temporarily by running a 12gauge wire from the horn relay (or the battery) to the ign sw BAT terminal to see if that eliminates the symptoms.

If it doesn't...

Pulling out the headlight sw draws current through other wires in the firewall connectors (junctions), wires which may also have poor conductivity at that junction.

Back at the ignition switch, the ACC wire is going to branch out to a lot of devices, some of which aren't fused, so that won't be easy to isolate and troubleshoot. With the headlight switch off, are there any accessories that are not operative right now? If so, they might be suspect and need to be disconnected, especially if they aren't fused (like the wiper motor, for instance).

The car was not in the process of being started when you reproduced the problem, so the ign sw "SOL" terminal probably isn't involved in the problem.
If your car has an automatic transmission, one branch of the SOL wire goes through a neutral safety switch, which could very well be problematic, but again, that only should affect starting unless you're getting crossfeed to that terminal from the others with the ign switch in the "on" position..

The two IGN wires go: one to the firewall resistor and thence to the coil; the other to a fuse, so those sections can be easily isolated.

 

[kpauley]

What we did with the iginition switch so we could handle it better was make extension wires, this way we could hold it in our hands and see how the switch was passing voltage. So we pulled the BAT wire from the connector to the switch with a wire to get 12V to the switch. Then, no other wires except that one connected we turned the switch to verify that 12V was coming out of the other connectors. This was the case, we were seeing 12V where we should be seeing it. Then, we hooked up one more wire, to the SOL terminal on the connector (we had just read 12V coming out there). Once we had it hooked up to the connector, the voltage dropped down.

Hopefully that makes sense, sometimes it's hard to describe this stuff.

Further isolation was where I was heading. We started some of that yesterday and it's probably the only way I'm going to be able to trace this stuff down. I want to do a closer inspection of that firewall connector though first, we were moving a little fast when we found that.

Manual car, so I guess that means there is not a neutral safety switch, correct?

Ken

 

[JohnZ]

Nope, no safety switch on a 4-speed. Sounds like you have a problem in the ignition switch internal contacts, and the bulkhead connector is a FAMOUS problem on C2's, especially the terminals for the 12-ga. red main power feed. When they get corroded, the resistance goes up at that connection, the terminals heat up, and actually melt the plastic cavities for the terminals, which loosens them up even more; eventually you wind up with a complete open circuit there and the whole car dies. Pulling both 8-cavity connectors (carefully, don't break the lock tabs) and cleaning all the terminals with a soft toothbrush and electrical contact cleaner (Radio Shack), then coating them with dielectric grease (Radio Shack) and re-assembling them can work wonders.

 

[kpauley]

I think we got it!

Well, when we last looked at this we found that major short behind the fuse panel but there was still some wierd stuff going on with voltage drops. We poked around tonight and were getting fairly frustrated but then we went back to the basics....the battery!

I had the started out and tested it again because we were seeing a big voltage loss. Tested fine. So we put it back in, hooked up just the battery and ground and jumped the SOL connection....nothing! Ran jumper cables to the battery from my other car and bingo, no problems. So I'm going to pick up a new battery and start putting things back together, testing as I go.

I think the short was a key find and it is probably what drove the battery to bad shape (it won't even take a charge). So, this weekend I'll be putting things back together and hopefully an end to this thread!

Ken

 

[Ken's67]

I would clean the area that the battery ground cable is bolted to the frame. If the ground from battery isn't that good, it could cause a voltage drop, and drain the battery. KTK

 

[kpauley]

The car runs again, saga closed!

Well, I took the car for a quick drive tonight, it runs again! The grounds all looked fine. I think the short behind the fuse panel and then the dead battery were the real culprits.

I was nervous about taking apart that fuse panel, but it's pretty straight forward. I would encourage people to check the wiring behind there.....

Thanks for the coaching.

Ken