Okay my boyfriend has a 1999 dodge intrepid with 172,000 miles on it. he bought a new battery but now the battery light is still on? do you know what the problem could be? also what could he do to get it started?

If the battery light is on while running the charging system is not working.you can check
with a volt meter,setting meter to dc volts & connect meter leads to battery.reading should
be 13.2 - 14.5 volts if lower than this your only reading battery voltage.check single red wire to the alternator it should read battery volts 12v.if battery voltage is present than alternator is faulty,if no voltage reading you'll need to trace & repair the wiring
note; battery should be fully charge before testing

good luck