brake light is always lit

[jessez]

I have another issue with the '92 k75s.  The brake light is always activated the moment I turn the key.  Neither brake being used seems to have any effect.  When depressing the pedal I hear a click, so I think the switch is working.  A previous owner installed an actuator which when working normally make the rear tail lights flicker then become solid when the brakes are used.  I don't know if there is a malfunction related to that, and am not sure where on the wiring that is even installed.  Anyone have any ideas?

[Jumpin Jimmy B]

On my 93 K1100 the front brake handle was NOT returning all the way to the out position. Causing the light to stay on.
 See if pushing the lever forwards makes the light out out.
 If it does, you are possibly due for a master cylinder rebuild at worst and at best you just need to clean the
hand lever pivot and lubricate.
 Also possible the brake light actuator is hung up a little bit also. Small plunger behind the front brake handle.

[jessez]

It seems to me that the hand lever is indeed returning to the proper distance. Another interesting tidbit is that about 40% of the time after initial start up, the brake light will be properly lit (dimly) and pulling the front brake will actuate the flashing tail lights but ALWAYS after that initial activation the center brake light will stay on solid and the tail lights will no longer flicker with brake actions.

[Inge K.]

To narrow down which brake lamp switch (or the magic box added by PO) is the source for your problem,
disconnect the brake lamp switches.....and see if it changes anything.

Rear switch connector you find behind RHS battery cover, front switch connector you find on the right side under the tank.

[Motorhobo]

This may not help you but I had a similar issue this morning. A few days ago, I noticed brake sponginess so I stopped to tighten the MC screws, one of which had come loose a few turns. I know -- you're supposed to tighten things properly -- not the point. Anyway, afterwards I noticed some free play in the lever and the brake light was always on as a result. Seems when I tightened the MC retaining screws the MC wasn't centered properly on the housing which impeded the free movement of the MC plunger. Loosened screws, retightened properly centered, free play disappeared, brake light works fine now.