under the seat is a yellow plug, take it off and put it back on a few times. most of the time its just a bad connection when the light is on and off randomly.
Mine was random at first. Then it was constant. I tried your trick of plugging and unplugging the other day and had no luck unfortunately.
2011 Mitsubishi Lancer GTS - DD mode
1991 Mitsubishi 3000GT - Many mods to come