Two things set off that light - handbrake & brake fluid.

Unplug the wires to the brake fluid reservoir. If that makes the problem go away, then your float switch is bad. (Unless the fluid was actually low...)

Take off your console around the handbrake lever. There's a little switch down there. Maybe it's bracket is bent so the lever doesn't hit it properly?

If it's neither one of these, it might still be insulation worn thru anywhere on that wiring. That's gonna be a PITA to find...