Headlights for 1957

**Dan D.** · August 26, 2011, 08:40 AM

Re: Headlights for 1957

Ted,
You don't say if this happens on low beam or high beam. Unless you have new repro headlights, current draw should be less on low beam, and no where close to tripping the switch breaker on either beam. The only way to measure the current draw of your headlights is to put an amp meter in series with the headlights. You can do this by removing the feed wire from the dimmer switch and putting a current meter in series. Harbor Freight sells a small VOM with a 10 amp scale for $5 or $6. Be careful you do not ground this wire or you will blow the internal fuse in the meter or wipe out the meter itself.
If you have old wires, they could be shorting in the auto loom sleeving, or anywhere else for that matter.
Are the terminals clean on the switch? You said you replaced switch, but if the spades are corroded, they can get hot and cause the switch breaker to trip, as the breaker is a thermal device.
I don't think the problem is your headlights. I think it is either bad wiring or corroded connections.
If you drove a 57 from Nebraska to Vermont, God Bless you. Please post the condition of your wiring and terminals. This will help. Put your fingers on the switch terminals after the lights have been on for a while and see if they are hot. Old wires are very brittle. -Dan-

**Theodore K.** · August 26, 2011, 02:06 PM

Re: Headlights for 1957

Thanks for the comments Dan. It happens in either hi bea or low beam and the hi beam indicator red light on the speedo goes out as well. I have ammeters, etc at home so will look in to that when I get the car home in October. I am going to put the old switch back in and try that tonight. If they don't cut out then it will point to the switch. If it does, then to the wiring. The reason I changed in the first place was that the dash ligh potentiometer was burned out. But for 28 years it has worked onkay. Only on this trip did it start to act up and after I changed to a new switch. I will take the new switch back home with me tomorrow and test it on the bench. Meanwhile I can live with the dash lights always on bright if I have to. Better than no headlights...LOL. It is the original wiring and I think this winter I may invest in a new harness. It is getting somewhat brittle but I really have never had a short circuit. There have been lots of splices, patches and who know what. Everytime I unwrap a harness piece I find this. I will let you know what the old switch does. Thanks again for your help.

We want to go home via the blue ridge parkway.Should be a good trip. I rebuilt the engine last fall and this trip I have had lots of problems and this headlight issue is just one of them. We are not afraid to drive this most anywhere but it is miserable in the rain as the car leaks like a sieve.

**Dan D.** · August 27, 2011, 08:30 AM

Re: Headlights for 1957

Based on what you just said, I believe your problem is the replacement switch. Seems to me there was a thread a while back about repro switches cutting out like this. What you could do is put the new dimmer rheostat in your old switch. Not too hard to do, but be careful if you take it apart. Detent spring and clips can go flying.

If the resistance wire is not burned out but it just plain doesn't work, then the problem is probably that the riveted connection at the ends of the coil are corroded so badly that there is no longer an electrical connection. What I did is abrasion cleaned the connection and then floated solder flux on it until I got the solder to flow. So now I have soldered connections that will not fail. While it was apart I cleaned and lubed the whole switch. I was able to re-use the complete original switch, which now works as good as new. -Dan-

**Theodore K.** · August 27, 2011, 10:50 AM

Re: Headlights for 1957

Dan, thanks for your additional comments. I want to update you again. Last nite I decided to re-install the old switch. As I was doing that, i moved all the connections one at a time from the new switch back to the old switch. Low and behold, when I moved the Blue wire (headlight feed to the dimmer switch) and then installed the switch and reconnected the battery, headlights would not work. After checking with a test light that I have along, I found the switch was okay. I now suspect the blue wire connector does not seat correcdtly. After fiddling I got the headlights working and they were okay all evening. Next trip out here to Vermont, i will bring a new terminal for the connector and install if needed. I am taking the new switch home and will bench test it to determine where the CB opens. If the CB is at the correct amperage then I am back to the wiring. I am beginning to feel that the problem is in that connector. I have to be careful not break it off until I have a crimp tool and soldering iron around. I am an electrical engineer and 2-way radio service guy so I have the tools and equipment around but just not with me. I will be glad to get the vehicle back home in October and correct these problems.

The rheostat for light dimming is burned out and open circuited on the old switch. That is really what started this change in the first place. I always thought if I could locate some resistance wire, I could rewind that rheostat coil.

Thanks for you help and on this matter. All the collective wisdom is appreciated. I will try to remember to update you when this saga finishes.

**Dan D.** · August 27, 2011, 04:49 PM

Re: Headlights for 1957

Okay Ted, sounds good. Make sure all those spade terminals are clean. If you measure the interupting current of your switches, please post it. Not sure if anyone has done this, but it is rumured to be 13 amps. Would be good to know for both your new and old switches. Do both the breakers. -Dan-

**Theodore K.** · September 7, 2011, 06:07 PM

Re: Headlights for 1957

Dan--Today I ran a test on both sides of the replacement switch from Corvette Central. I paralleled head lamps and resistors to get 14.4 Amps @12.7 VDC from my supply. The CB on each side of the switch held that current for over a minute without tripping. I am convinced that it can support over 13amps. Perhaps a longer time would have eventually tripped the CB but if it were 13 amps, I would have thought it to trip in that period. I am now convinced that my problem is in the push on connector that goes on the switch top. I will have to replace that connector next trip out there. Thanks for your help and comments.
Ted

**Dan D.** · September 8, 2011, 08:14 AM

Re: Headlights for 1957

Ted, You can touch the breaker contacts and see if they are warm or hot. Also touch the spade connector in the car. Seeing how they are a thermal device, they will be hot in order to trip. So if the spade is your problem, it will be hot. Good info - thanks. -Dan-

**Theodore K.** · September 19, 2011, 10:10 PM

Re: Headlights for 1957

Dan--I reran my test and touched the contacts while pulling 15 amps. They never got very warm at all and after a minute or so, they did not open up. I could not run a sustained test because my resistor load was getting hot. (nothing to do with switch). Consequently I have concluded that the cutting out problem was most likely a bad connector lug or oxidized crimp on the lug terminal. Since I am now back with the car in Vermont readying it for the return home, I have changed the connector out to a new one. I crimped and soldered the wire to the connector. I put the new switch back in the car and drove it tonight with high beams on. No cutout yet although 1 night does not make a good test. If this cutout returns I will write again. I hope this is finished. I want to thank you and others for your comments.
Ted

**Dan D.** · September 20, 2011, 07:32 AM

Re: Headlights for 1957

Hi Ted. Sounds good. Let us know how you make out on your return trip. I envy you driving your 57 all those miles. Hope I can do the same in a couple of years.

Good info on breaker capacity. It would be interesting to know what the interrupt current of this breaker really is. Thinking about it, I would think the current rating would probably be quite high to guard against nuisance tripping, which would be a disaster with headlights. It probably was designed primarily to protect the wiring against short circuits. -Dan-

**Theodore K.** · September 20, 2011, 07:51 AM

Re: Headlights for 1957

I will do that Dan. The trip home is about 2600 miles so it should be interesting.

I have the old switch out again. I think for kicks I will test that one as well as I have the test set up. I may round up a couple more headlights and put them in the string of parallel headlights to increment the draw. It is pretty easy to do. With headlights I don't have to worry about the resistor getting too hot. It was put in parallel to trim out the current draw. By the way, I tested each headlight with a ammeter before puttin gin parallel so I know fairly well. The supply held its voltage pretty well and maybe only dropped .6 volt from no load to full load. That lessens the current slightly but not too much. Anyway fun testing.
Ted

Headlights for 1957

Headlights for 1957

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