My wife's 04 Elantra starts intermittently in the mornings. When it doesn't start, you turn the key and nothing happens, no crank, etc. However, it will start when jumped. I don't think it's the alternator as the lights don't dim when running, I had the battery and the starter tested and both were good. Any ideas?

 

sounds like the battery test wasnt right. that's a dead battery. Depends where you take it because batterys can be tested good but require a charge (trust me i have to deal with all this equipment daily for warranty at the dealership i work at. Its all the same equipment/software) If the vehicle starts with a jump then the battery is at fault. The alternator is ok as long as it puts out over 13.7-14.0v. Also check to make sure there's no draw killing the battery overnight. Ive seen bad factory radios cause intermittent draws since they have a direct link to all time battery