It's anything and everything. Things that have triggered my Brake/charge combo on my 83, bad alt., various emissions related stuff, vacume switch, carburator out of adjustment, too rich, O2 sensor, and just yesterday choke not working. I have an old school Toyota mechanic near me and he really knows 80's Toyotas he told me the charge/brake light is a check engine light so it may not be the charging or braking system at all.
