Mid year brake light switch

[Ed K.]

My 66 brake light switch frequently fails. Over many years I've replaced it with either a Delco part or Standard. Typically I find performance is erratic - works, doesn't work. works....etc. Taken switches apart to find contacts working, put it back in car and it works for awhile, not at all or maybe a month or year. Same occurs with new switches. Living in a semi-urban area it's important to know lights are working so I added a LED into the circuit mounted below the dash and visible while driving. When installing new Delco and LED the last time I noticed the switch plunger was not sitting squarely on the brake pedal. Ah ha, that's the problem. Plunger not moving properly. Was able to center the plunger. It lasted a year. Last week connected a new Delco into dangling wires and all OK. Today tested it before fully installing into mounting bracket to find switch not working. Continuity tested the failed Delco switch and find contact intermittent. Anyone else have this issue? An electrical engineer friend examined this and is baffled. Car is only driven about 500 miles a year.

[Richard M.]

Re: Mid year brake light switch

Ed, You are not alone. For years I have found both Delco and Standard to be poor quality replacement switches. Here is what I found when restoring a '67 some time ago. I gave it a quick test before reinstalling. It failed and I found this. The car had no brake lamps before I took it apart. I now look for NOS or used originals.

[Ed K.]

Re: Mid year brake light switch

Thanks. My rear lights work, just not brake lights. What do you mean by car had no brake lamps? Bulb brake light filament missing?

[Richard M.]

Re: Mid year brake light switch

Thanks. My rear lights work, just not brake lights. What do you mean by car had no brake lamps? Bulb brake light filament missing?

Ed, Because the switch was broken it didn't have functioning brake lights/lamps.

I decided to open the switch to see why. As you can see the contacts were broken. The switch design seems inadequate to keep alignment. Moving the spade connector terminals can move the internal contacts.

I've seen this problem on many switches.

Rich

[Ed K.]

Re: Mid year brake light switch

Yep, you're right about moving the spades. Just did a continuity test with a bad new Delco switch. Touching with probe at first nothing. Moving one spade a hair completed circuit.

What leads to intermittent contact? Switch is reasonably held rigid, connectors do not move or apply any force on spades.

[Richard M.]

Re: Mid year brake light switch

Yep, you're right about moving the spades. Just did a continuity test with a bad new Delco switch. Touching with probe at first nothing. Moving one spade a hair completed circuit.

What leads to intermittent contact? Switch is reasonably held rigid, connectors do not move or apply any force on spades.

Ed, I don't have a answer, but I have a opinion....

I think the original design was adequate along with the electrical contact/lead materials used. I would imagine the original material of the contact/lead assemblies were robust and likely a hardened beryllium copper able to withstand continued operation.

Unfortunately whoever is making them today must use inferior contact materials thus leading to early failure. So typical of many reproductions today. Material quality is not what it used to be.

Rich