VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Brake light switch

I am replacing my brake light switch and am getting conflicting info as to whether or not to wrap the new one with a little teflon tape. Some say don't do it but then the part arrived yesterday and has a narrow band of teflon tape already wrapped on the threads. It is a high quality switch and I don't think the company would have wrapped it if it wasn't O.K. In the past, I have never used anything on the threads. Any helpful ideas?

That extra sealant will help minimize leaks. It will not interfere with the electrical operation of the switch.

The brake light switch closes internally to pass current through it and on to the brake lights.

There are some pressure switches that are basically “grounding” switches. The current passes thought the single terminal on the switch through the body which completes the circuit to ground. In those cases you need to be very cautious about using sealant or tape. For those I put tape or sealant only on the upper potion of the threads. I leave the tip uncovered so it can ground.

After you have replaced the switch check the operation of your brake lights. I expect you will be surprised how far down the pedal has to go before the lights come on. The issue is that most hydraulic brake light switches that you get today require at least 60 and maybe even up to 100 psi to close. The original switches on these cars operated in the 20 to 30 psi range. Overall the brake system pressures were lower than what was used even on the 60’s. Today most vehicles use a mechanical switch to activate the brake lights.