Question: C3 Brake light switch again

[ARW]

1971

Was the original brake light switch #3954246 100% plastic like the replacements? I can't remember for sure, but I thought it was cast metal.

After about 5 new switches in 33 years it occurs to me something could be wrong. I adjust it to make contact with very little pedal travel. Could that be ruining switches? Connectors are tight, ground on frame is clean. Jiggling it seems to fix for a few days, then no lights again. Anyone have a recommendation for conductive grease to put on connectors, or would that help? I'm sure this car doesn't get driven enough.

 

[bill81vette]

I ALWAYS put electrical grease on my connections!!!!
I have my brake lite switch adjusted so when the pedal starts to move away from where it lives,the lite is activated!

 

[Vettehead Mikey]

What exactly fails in the switch?

 

[ARW]

They are sealed up - so hard to say. Just fails to complete the circuit. The only one I autopsied didn't look bad inside, but it still didn't work everytime. Nothing broken or burned. Looked like it was designed for 2 sets of points (like old ignition points) , but only had one set installed. IF either connector tab get moved outside the switch, the points inside could mis-align, but it would have to be way off to cause it to fail. Unlikely as it seems, its as if sometimes the points make contact but juice doesn't flow. I'd like to blame something other than the switch. Do you know whether the factory installed switch was all plastic construction ?

 

[Vettehead Mikey]

The one on my '73 is all plastic and was there when I bought the car in 1990ish. Still works fine.

 

[6880 Mike]

...I adjust it to make contact with very little pedal travel...

Supposed to be about an inch of pedal travel, isn't it?

 

[Evolution1980]

I'd love to help, but most of my time is spent mashing the gas pedal and not the brake. I'm not familiar with what the brake pedal really does.

 

[JohnZ]

Supposed to be about an inch of pedal travel, isn't it?

Spec is 3/8" to 5/8" of pedal travel to close the switch contacts.

 

[ARW]

Thanks for the info. I've always had it more like 3/16". I'll try 1/2" with the new switch.

 

[JohnZ]

Thanks for the info. I've always had it more like 3/16". I'll try 1/2" with the new switch.

The spec I posted is for a midyear - if the C3 is different, it'll be shown in UPC 12 in the Assembly Manual on the sheet that shows the brake light switch installation.

 

[shrekviper]

1969 AIM shows .26-.64 inches of travel (1/2" to 5/8"). Measured at the bottom of the pedal. (1969 UPC 12/B8). I'd think a 1971 is the same...

 

[ARW]

I'm wondering if the original looked like this photo:

http://i.ebayimg.com/03/!BcoY+C!!2k~$(KGrHqUOKjkEq5UJorjkBK1SrQZ3cg~~_12.JPG