2007 Mazda 3 won't start
 

last weekend I tried to start me car and it wouldn't start. I gave it a jump and it started fine all week. Then, Saturday I went to start it and it wouldn't start again. I jumped it and it started. I now have to jump start it every time to get it to start. Anyone know what it could be? I bought the car about 2 months ago, and the dealer had put a new battery in it.

I'm guessing it is not charging the battery. Suspicious that it needed a new battery after only 3 years. Have the alternator output checked at your local garage.

I agree with alex that it's suspicious that it needed a battery after 3 years - though it is possible someone forgot the lights and killed the battery or something.

When it doesn't start, do you get any dash lights? does it just not crank? do you hear a click from the starter? or does nothing electric work at all?

Is there any evidence of 'extra' wiring in the car - like from someone adding a stereo? I've seen a bad connection at the battery cause a no start condition - though all the other lights work fine. Happened to be from a crappy car install job.

dash lights and radio come on, there is a clicking noise also, It just won't turn over. I had the alternator checked and it's fine. I've had it in the shop now for 2 days, they are still trying to figure it out. Said it almost looked like a short in the battery???

If you have all the lights dim (like the dome lights) when you try to crank - i'd think of a bad battery - or a shorted starter. I'm assuming it's a starter issue, when you have someone jump the car, their car is running, so the voltage may be just high enough to get the starter to work. But normally your battery just doesn't have quite enough voltage.

The clicking is probably the starter solenoid trying to engage - so i'd assume a new starter is all it needs.

I'm very suprised it takes multiple days for someone to find the problem.

I got my car back yesterday, it was a bad battery. The dealership I bought it at must have put a used battery in it. Thanks for everyone's help and input!