edfrye

The headlight switch in my 1969 Corvette burned as shown in the photo THAT I CAN'T SEEM TO COPY below. I'm trying to determine if it failed of old age or if it was overstressed due to an excessive load. I've made several volt/ammeter tests as shown in the photo. IF i CAN EVER FIGURE OUT HOW TO COPY THE PICTURE You will see that all tests were made from the headlight plastic connector. I've identified the test points on the connector by noting the color of wire at each connector. I did not measure the current but that can be calculated, from the data in the photo, using ohms law e.g., Voltage = Resistance (ohms) time Current (amperes). I'VE SAVED IT AS A .JPG AND AS A GIF BUT NEITHER WORKS.

HELP, HELP, HELP
I CAN'T SEEM TO COPY THE PICTURE. I SAVED IT AS A JPG AND GIF.
ED

bruiser

Go to http://tinypic.com/index.php
Choose file, upload picture, click on image code, paste image code in to your reply.

7T1vette

Most likely, the headlight switch overheated due to corroded/carboned-up contacts which increased resistance and created the heat. The only other area that could cause a similar excessive 'load' on the headlight system is the high beam switch system. You might want to check that out before you finish your repair.

edfrye

I believe you hit the nail on the head. The plastic headlight connector is melted at the jumpered pin connection. That is, where the one of the pins has the 2 brown wires. As you know this jumpered connection depends on a jumpered direct connections between the 2 pins. The pin that connects directly to the rheostat is where the plastic melted. Looks like that "friction' connection got too much friction. Regarding the dimmer switch. It also failed - I'll look at the schematic but why do you think the dimmer switch could be the problem? Thanks
Ed Frye

edfrye

I checked the resistance between the 2 connected pins on the switch and it was virtually zero. I did notice that the pin connection that connects directly to the voltage input to the rheostat is the one that is severely burned at both the plastic connector as well the pin itself. The rheostat got so hot it busted the insulator. Since I can't figure out how to post the picture on Corvette forum but was able to send the picture by email, from his link on corvette forum. With your permission I'd be glad to send the picture to your email address shown on Corvette forum.
Ed Frye

RobbSalzmann

edfry's image:

edfrye

Rob, I see you got it. I have a new headlight and measured the resistance in 4 positions as I rotated the switch. They are as follows:
1) All clockwise on rheostat to the instrument lights off position -open
2) All clockwise on rheostat to the end of the rheostat -2.3 ohms
3) Complete Counter clockwise postion - .4 ohms maybe my meter
4) Abt Midway clockwise position - 1.1 ohms
Power = I squared x Ressitance.
Probably best to be in the complete clockwise or counter clockwise position when there is no need to dim or brighten the console lights. do you agree. AND Thanks for all of your support
Ed Frye

RobbSalzmann

Glad I could help.

I hope you can get your electics sorted out.

edfrye

Robb, Thanks a million. I'm now waiting for comments.

RobbSalzmann

At this point I would ensure the fused part of the circuit is properly fused and install a known working switch.

edfrye

First, thanks again for posting the picture I sent you. I'll trace the headlight circuit on the schematic to see where to test it other than at the plastic connector. I did test it at the headlight switch plastic connector. At the console lights - I installed all bulbs with a rating of .27amps at 14 VDC. As you know the current will be a little less at 12.7 volts. The .27 amp bulbs were the bulbs that drew the least current of all the bulbs I saw.
Ed Frye