when battery and brake light comes on while driving what does that mean on 2001 Mitsubishi Montero Sport

i have a 2001 mitsubishi montero sport

Asked by for the 2001 Mitsubishi Montero Sport
2 answers
Mine was the alternator.Go to an Auto Zone, OReilly's or whatever is near and they will check it for free.
I have a 2003 Misibishi sport battery and brake light comes on and off