coreyhayman

my battery wont charge, car was fine today then on my way home i looked at my volt guage and my battery light came on and it wont charge at all, could it b my battery or maybe my alternator?.......ne tests i can do onmy own to figure it out?...whats a new alternator for a 91 civic go for roughly?.....thx guys

coreyhayman

im also throwing a code 20.electrical load defective circuit....yada.yada

imported_loudsubz

grab multimeter

measure voltage at battery with car off

turn on car

measure voltage with car on

you should get around 1.5-2 volt increase with the car running, around 13.8-14.4 volts

if you dont get a change ur alt is dead or going

G_S_B_T_C_C

probably your alternator the only way to check is with a volt meter, you can get rebuilt alternators for like $110 bucks or used ones for like $60-$70 what kind of car you have. Code 20 is a common code in dx - si engine swaps, so if you done that swap don't worry about it.