The purpose of this article is to help locate and troubleshoot the front brake switch on your Harley Davidson. The most common symptom is the brake light is always stuck in the on position, with neither front or rear brake making any change to the taillight.
The front brake switch is located in the right hand control as shown in picture 1.
The front brake is a mechanical switch with an internal spring. There is a flat tab on the front brake lever that engages the switch and keeps the contacts in the switch open shown in picture 2. When the switch is fully depressed the brake light is off. When the brake lever is engaged the lever pivots allowing the switch to release. When the switch is released, the contacts are closed and allows 12 volts to feed the brake light circuit. Picture 3 shows the brake switch plunger sprung out in the on position as if the brake was engaged.
How to Test:
Remove the brake lever snap ring, pin and lever. Use your finger to actuate a release the switch and watch brake light function.
How to fix:
Mostly this is due to the misalignment between the master cylinder and switch housing. Loosing and adjusting the switch housing normally resolves this. If not it could be the switch needs to be replaced or the master cylinder serviced.