Chevrolet Repair: alternatr, chevy blazer, 2000 chevy blazer

Question
I have a 2000 chevy blazer LS   and i  put in a system in it ever since i been having trouble with the alternatr.First i got a new battery for it then  they said i need a  alternatr so i put one and i still have the same problem and they keep telling me diffrent stories and right know the blazer doest wanna start its the alternatr, i went to change the bettery they gave me a new one i put it in it started but my batter light is on ?    please help

Answer
Hi Raymond, Test for power at the back of the alternator at the (big red wire). It must have power and should also be checked for good amp flow if it has power. To check amp flow you can use a head bulb and just use the red wire for power and ground the other wire, bulb should be bright.

Let know what you find

Mark