The stock emergency flasher can fail "ON". Inside the switch, there is a contact that rides in a groove along the length of the switch when the red button is pushed. Theres an internal spring that puts a constant pressure on the button, and this results in the plastic switch body bowing outward slightly. When the body bows, the contacter pops out of its track and the switch activates. If this is what happened to yours (as in mine), the fix can be done two ways. First, make a wiring diagram of the multitude of wires that connect to the switch. Then, disconnect all the wires, unscrew the trim ring and pull the switch out the front of the dash. By bending tabs, the switch can be disassembled. The contactor can be shimmed outboard to follow the distorted switch body, reassembled and the unit will work as designed. Or, a small screw-type hose clamp can be fiddled around the switch body while its in the dash and slowly tightened while pushing the button in. At some point, the hose clapm will restore the internal clearances and your switch will work properly. But you gotta 'feel' for the point where the sliding contacter re-enters the groove in the switch body, or you risk destroying your switch. There is no known interchange for a cheap replacement, either and OEM switches are expensive. Jamming the button in with a toothpick risks holding the button in TOO far, which then disconnects the tail lights and attracts police.
