1975 S burning through brake light switches

[RNajarian]

I'd appreciate your thoughts on my brake light switch issue

In March 2014 the original brake light switch of my 1975 S went out (either at 135,000 or 35,000 miles) I replaced it with an OEM product I bought from our host. The installation went well and the brake lights worked as expected.

In January 2015, about 10 months and 600 miles later, that part failed. Pelican was quick and efficient in getting me a warranty replacement. That part also went in without a hitch and worked as expected for 8 months (approximately 500 miles)

So two switches go bad after roughly 500 miles and 9 months.

What am I missing? Could I be installing he switches wrong? The moment arm on the switches are adjustable, do they need adjustment or is the factory setting correct.

Thanks for your insight

[wolds]

Sounds like to much current going through the switch. Hopefully you have a service manual for the car so that you can look up the brake light circuit. If not you should be able to find it online. Without swamping you with too much info you are looking for loose and or corroded connections in that circuit. This will cause a current rise in the circuit and burn out the switch. You will need a multimeter to check. One thing you could try early on is to pull the fuse and put your meter (set to current) in place of the fuse. Select a high current setting and activate brakes. Read the meter and post that info back to us. Not sure how many watts the bulbs are but you have two of them so whatever the rating is it is double that and then convert to amps(I) to compare to what you are reading on your meter. You should be reading on your meter approximately this value (I). If it is much greater then expected you have additional (unwanted) resistance in the circuit that could be caused by oxidation or a loose wire.

[Jcslocum]

That must be the issue, a dirty connection OR ground at the tail lights. These need to be cleaned and sprayed to protect them. There are some excellent cleaning and protecting sprays out there for this. Nothing will be better than a good sanding or scotchbrite of all connections. Each plug on the way from pedal to bulb will need it after 40 years...

[Dr DIY]

Originally Posted by Jcslocum

Nothing will be better than a good sanding or scotchbrite of all connections.

And then a tiny amount of dielectric grease on each plug when re-assembling.

[john walker's workshop]

Offshore crap.

[RNajarian]

Sorry gang, I mistakenly chose poor words in the original title

Though the issue could be electrical, it appears the mechanism (switch) itself is the problem. The moment arm does not "click" or return to its original position when you push on it.

I will try and post photos

Sorry for the confusion

[RNajarian]

I removed the bad brake light switch. The moment arm (lever) is sloppy and does not click. See photo compared to functioning 1983 SC brake light switch. Notice the SC switch is in the middle of the unit and the bad switch is resting on the bottom of the unit.

I called Pelican, and as usual they were fantastic. The replacement switch is already on its way . . .

but what can I do to prevent if from happening again?