'87 K100 Brake Light Warning
does not shut off. When only the front brake lever is applied, the brake light comes on. When only the rear brake is pressed, the brake light does not light. The brake light does light when both brakes are applied.
In the meantime, the brake hazard light is constantly on and does not turn off when the brakes are tapped. Where do I begin to fix this problem? Is there a rear brake sensor that needs adjusting and if so, where is it located?:dunno
Sounds also to me like rear brake switch.
Either type leads a hard life. They rely on metal to metal contact to turn on the brake light and turn off the dashboard "brake light failure" light. New switches work great because they are clean inside. As one guy suggested, solvents sprayed inside like WD40 can sometimes restore the "metal to metal" contact inside needed to work properly. My 85 has the round plunger type on both front and rear brakes and rear one has responded to solvent and "working it."