88 4runner weird stuff

[4runninAZ]

ok today i just finished a day of
some 4 wheelin splashing in a river
sliding in the mud in my 88 4runner
i havent had any trouble with this since
ive had it, but we started to get back on
the highway so before i jumped out checked my fluids everything good to go
then when i turn it on it shows battery charge light and emergency brake light
its a brand new optima and e-brake is not on but when i started moving it turned off then further down the high way they both turn on again the engine and everything sounds good, but the lights do seem dim
im thinking it might be the alternator
anyone have any idea thanks

 

[the_dingman]

Both the battery and brake light indicate either a faulty alternator or a broken belt for the alternator.