My roommate’s 2004 Saturn ION has a new battery, but after driving around for a few days the battery was dead.
We were able to jump it, but only after leaving my car running and attached for an hour.Then it started and ran fine.
We think it’s the alternator. Is there anything else we should check before replacing it?
I’d sounds like its the alternator.
The roomate could drive the car to a local oreilly auto parts or Autozone and get the alternator and battery checked. Both can be tested without it being removed from the vehicle.
Agree with Paul because you were able to charge the battery with your car, but you could also check the current draw while the car is off using a multimeter. It could be an alarm / light not going off because of a busted switch or a short / blown fuse.
Are the battery cable connectors clean? If the connectors are corroded or dirty, could also cause the battery to not be able to charge from the alternator. This may also explain why took an hour to jump-start.
Some of the GM side-post battery connections get corroded on the inside.
I wouldn’t buy a part till you were sure. Nothing worse than owning a replacement alternator and finding out you had a different issue. I had a B3000 that had a rear tail light short that would draw the battery down over about a day. You would never of known it as the bed camper covered the light. we found it out after seeing a draw on the battery when the car was shut off.
Next time it’s dead try to check the battery voltage. It could be a bad starter instead. A thump to the starter with a broomstick should get a marginal starter to kick over.