Brake light always on

[Steez]

1997 gsx750f, my brake light illuminates as soon as I turn the key. Both bulb filaments stay lit (ie.the taillight and the break light). I have checked the switches on the handbrake and the footbrake, and both are good. I have also disconnected them both and the taillight stays lit.

One other weird thing, if I connect the switches, depressing the footbrake has no effect. However using the handbrake pops the 10a fuse that is connected to the taillight.

Using a multimeter I can see that the wire going to the taillight which controls the brake portion is always hot, which it shouldn't be unless a brake switch is activated. Only the running light wire should always be hot (which it is also). Also, both wires going to the footbrake are hot, when only one should be. The wires to the handbrake are proper (one hot the other dead), which makes it even weirder that using the handbrake pops the fuse.

I don't think it can be a coincidence that the footbrake wires are hot as well as the brake light wire being hot when they shouldn't be. It must be related. All wiring looks stock and intact, but I haven't started unwrapping wiring harnesses yet.

Anyone have a clue or a similar experience? Hopefully that all makes sense. I've been looking at the problem for too long. But basically its definitely not a switch because both are disconnected and the brake light is still on.

Help? Please

Oh and the bulb is fine before anyone asks, I've replaced it

[92xjunker]

Noob info: light switches, either at the hand control or foot brake, easy to test with a meter, pull the wires, measure continuity across the pins should show "OL" when not activated. Check the hand control plug and the pins, race back from there for loom chaffing you may have to split the loom to find a short.

[Steez]

Yeah switches are both good unfortunately. Wish it was that easy

Stays lit even when switches aren't hooked up, so the wire's getting juice from somewhere.

[92xjunker]

Unplug the hand control, still lit? Inspect the wiring for pinch points and chaffing. May have to split the loom to find it, not hard to do, just did it for a signal issue on the 88. Op, was an idiot.. Lol

[Steez]

In case anyone's interested, I literally unwrapped every wire loom and electrical tape wrapping. Some idiot preivously spliced the footbrake and brake light wire into a hot wire leading to the instrument cluster. That's what was causing the constant brake light. Same idiot also spliced one of the handbrake wires into a ground. So when you pulled the handbrake, completing the circuit, it put a power to ground, popping the fuse. Re-wired the entire braking system and good to go now.

The only aftermarket things on the bike (I just bought it, they were already on it) are a Vance exhaust and flush led front blinkers, so somehow all this mess was created with the previous owner just changing the front blinkers!! How hard is it to replace blinkers hah?! Just cut and splice 2 wires per side. But anyway.

I'm no electrician but holy shit what a mess. I think I memorized the entire wiring diagram for this bike. Would have been much easier if it was a $10 switch or a pinched wire. Just need to mount a Metzeler front tire and good to get inspected now at least.

[92xjunker]

Good, you found the problem.

[Steez]

^yes, finally, thank god. I got a great deal on the bike because the previous owner didn't want to dick around with this issue. I figured it would be something simple like a switch or pinched wire, but at least I figured it out. Your advice was spot on, just inspect & trace the wires from the source to the issue.