VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt Sudden loss of power

Along with the annoying intermittent charging problem that I'm experiencing (details in an earlier post) I am also experiencing occasional sudden losses of power. The engine will be running and everything is working fine when the power just goes away, the engine stops and the gauges all turn off. There is nothing that I've found that works to get the power back on other than waiting about 30 seconds or so and then trying again. I can not cause it to fail and I can't make it work again other than waiting.
It's as if the ignition switch is turned off, could it be a problem with the switch?

Kelly

Yes it could be the switch or an eletrical connector.What year car is this???Will help to know

Oh yeah, the year, sorry, '38 Chevy Coupe. Fairly new wiring harness, I've checked and re-checked all the connections from the battery to the tail lights and replaced the headlight switch.

How about trying a different coil?

I would take a very close look at the headlight switch connections. I would change the fuse also.

Check the condition of the wire inside the eletrolock cable.It runs from the ignition switch to the top of the coil-Its also part of the ign. switch.

The man said the guages go dead indicating a complete loss of electrical connection from the battery - or IN the battery. Better recheck those connections to the battery. Maybe heat is causing a separation in the battery itself. Next time it goes dead see if there is voltage across the battery terminals. Then check at the starter, etc.

It seems to me that there is a loose connection or a corroded terminal. Check the ends of both battery cables and the ground from battery to frame or engine . The woven ground straps sometimes corrode to the point where there is no ground, also the connection on the starter switch that goes up to the ampmeter, I would disconnect the ground cable and systematically disconnect , clean and re-connect each terminal from the battery to the input of the ignition switch. You may also use a 12 gauge long jumper (with a large and a small alligator clip)from the battery to jump those connections to the + side of the coil and see if that makes it run. Does the starter have power, will the starter crank the engine? A good test to see if there is power inthe battery is try to honk the horn, it is usually connected independant of the igition switch

As a matter of fact, the starter does have power, because I have found myself trying to restart the engine before noticing the gauges are dead.
I have traced and cleaned all of the wires and their connections from the battery to the ammeter, and have inspected all the wires from the ammeter to their various destinations.
Unfortunately this is an intermittent problem and it fixes itself in less than a minute so it's hard to try many remedies, and because it usually happens somewhere in traffic I'm usually preoccupied with trying to stay alive and not thinking too clearly about diagnostics. My normal way of fixing things is usually to start by replacing the most expensive parts and then work my way down till things work again. Not very practical.


Kelly

Well don't think you are alone, after replaceing all of the expensive parts, then you will have to do like the rest of us do, get back to basics and check the connectors and wires again, I suspect from what you say and elimanateing the starter back to the battery that JYD's suggestion that it is either the electrolock or the switch itself, since the gauges go dead it probably isn't the coil.

I would hook up a wire to each of the ign. switch terminals.The next time it goes dead connect the wires together to eleminate the switch contacts and see what happens-kind of a hot wire deal

Thanks for the advice guys, I will start checking connections again and tracing wires, but I have one more question, what's the electrolock?

Kelly

That's the armored cable assembly that goes from the ignition switch to the top of the ignition coil. Actually, the electrolock consists of the ignition switch, the armored cable itself and the cap on the end that connects to the ignition coil.

I have only a 14 gauge wire running from the ignition switch to the coil and it doesn't look like anything special. Could that be my problem? And where do you get electrolock cable?

Kelly

It could possibly be your ignition switch giving you problems. And, you can find electrolocks in the "Parts For Sale" section of the G&D from time to time and I have also seen them on eBay as well.

Follow Gene's instructions. Hot wire around the ignition switch. The Instrument panel gages are powered through the ignition switch as is the Coil. It was stated that the starter will still crank the engine when the engine stops and the gages quit working. That makes me believe the battery is still functional. My theory is that the igintion switch contacts are experiencing a thermo disconnect, for what ever reason, that repairs itself after a short cool down period.

If you don't have an electro lock, what are you using for an ignition switch and is it rated heavy duty? Perhaps Oldie and Gene have hit upon the problem.

Well now I guess I'll have to go check and report back. It's an on-off only but whether it's origonal equipment is beyond me at this point. Looks just like the universal ones they sell in the catologues.

The original switch with the eletrolock cable coming out of the back of it has a provision for a light socket in the housing.It is lighted at night when the lights are on.The part you see in the dash is flush with the dash with a slight space around it .The key originaly was the same as the door key.Just above the key slot and to one side the is a tiny hole.The correct eletrolock fits 1937-39 cars.If you are lucky enough to find a new one it will also require finding the lock cyliner as it came without one.The lock cyl. comes uncoded-no tumblers-so a locksmith could recode it to your door key.The eletrolocks are expensive and hard to find.A new universal switch may be best for now (if needed).They are available from www.fillingstation.com

Actually the electrolock and the light socket are two different items. The light socket is a reflector plate that has tabs that mounts behind the throttle and choke cables and the nuts that hold these two cables holds the light socket plate in place. The electrolock mounts to this plate via two small screws.

There was a NOS electrolock on e-bay last week or so that also came with the lock core. First one I have seen in 6 years. It didn't go cheap.

Brian

What's the deal with the Eloctrolock cable thought? Mine is clearly missing, I just have ordinary wires running from the switch to the instruments and the coil. Do I need more?

I'm not going for 100% origonal condition here, I can't afford it at this point, I would just like to keep it mostly stock and to be able to drive it around town, no more than a couple of thousand miles a year at most. Maybe when my son gets older we can work at cherry-ing it out together.

Kelly

Kelly, Installing an eletrolock would also require the proper coil to attach it to.The top of the coil had a locking device for the eletrolock plus a wire terminal on top.If your present coil has both wires attached at the bottom it will not work.I agree with you-If the car is presently wired for the conventional switch I would leave it that way-just replace the switch with a new universal if necessary.

Brian, You are 100% correct on the light .I should have remembered that after installing the glove box on my '39 and the light getting in the way.The later cars had the socket plug into the switch........have you made any progress with your horns???

Thanks for all of the good info guys, I'll be installing a new ignition switch straight away!

Kelly

Chevnut-No, no progress on the horns. I'm still having trouble with the generator. I ran a test lead from the generator positive to ground and didn't get any spark. I don't know yet why. Consequently the horn problem has moved to the back burner. Not to mention the oil and gas leak and the oil leak from the steering box.....

Brian

If you have a spare I suggest you follow up on the coil option. Had a later model car that would do the same thing, itermittent, would not restart while coasting but if you waited a few seconds and hit the starter it would run again, might do so for days with out a problem. After consuming a six pack or so, and leveraging the friendship of the dealer service manager we found the problem. I do not understand the loss of power to guarges unless there is a cross up in the wiring however.