I currently have been using this type brake light switch in my 37 Ford sedan. I know things wear out over time, however, this type switch seems to last a couple years, and then ****. I've taken them apart and for the most part, the plastic that holds the connecting pins (black part in picture) is crumbly and kind falls apart, along with the inner contact piece having pretty much burnt up ( maybe from arcing). Mechanically, this setup has worked well for the past 25 years, but electrically, not so much. Any thoughts of the effects of 12v over 6v being an issue. I'm not sure how long these lasted back in the day (late 40's - early 50's). I have the unit mounted under the floor, at the point where the pedal comes through the floor, but IMHO, I don't think it's getting corroded from the elements of weather, but more from the physical electrical contact inside the unit. Also, not sure if it's a quality issue of the aftermarket products. Any ideas? Thanks in advance.
Find a GOOD used Delco from a pre '59 Chev truck. Lube it with RCBS case sizing lube, adjust the arm, & it'll last forever.
It is probably not 12V that is your problem, the enemy of an electrical component in your case a switch is Amperage and not Voltage. 12v pulls less amps. Your enemy is most likely pollution, hydrocarbons are extremely hard on plastic and rubber components. I still prefer a pressure switch in line over a mechanical but maybe that is just me.
Halogen lamps is the issue.... Those draw about twice the current of conventional lamps and that's what is killing the switches. Either switch to conventional lamps, or use a relay to energize the lamps. If you're using these as turn signals also, you'll need two relays. My avatar was fitted with halogen lamps when I got it, they took out two switches before I figured it out. I switched to regular lamps, no more problems. I also can't tell any real difference in brightness with the regular lamps in there...
Most brake switches are not designed for high amperage, and should be used with a relay as already noted, but the waterproof SW-42 from Ron Francis is. I use this on my '32 along with halogens and have one installed on my '40 project. Very high quality and easy to mount. No need for relays. SW-42 WATER PROOF BRAKE SWITCH Fully Adjustable & Water Proof Mechanical Brake Switch
Brake light switch shouldn't have an issue with Halogen lights unless you are running a lot of high amp stop lights like an Oklahoma semi might have. As that switch is exposed to the elements under the floorboard just as the same switch is on my AD Chev truck I'd say that being exposed to weather and engine heat probably has as much to do with it's early demise as anything else and the possibility of lower quality replacement switches now than came with the vehicles has a lot to do with it. As far as the inline hydraulic Ford style switches, I ran one of those for a lot of years on my truck and replaced it every year as they fail on all too regular of a basis or at least the ones I had did. That was behind the master cylinder in a T in the line on the frame rail under the truck so exposure to the elements may have come into play there too.
I've had mixed results with the hydraulic switches failing, and they are a much bigger pain in the *** to replace than a mechanical one. I think the Chinee switch quality has a lot to do with it on the OP's question. I pull them at the salvage yard if they are Delco and clean them up. They seem to last much longer. This all ***umes through the floor pedals. For hangers I use more modern switches that go under-dash.
You only need one relay. The brake switch feeds power to the turn signal switch which distributes it to the tail lights. Use the relay to feed the signal switch and the brake switch to control the relay.
So now you've moved the overload to the turn switch..... That's why I suggest two relays, one for each side.
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