Chrysler Repair: 2003 PT Cruiser starting issues

Question
QUESTION: My 2003 PT Cruiser bought in May 2014 has a 2.4l engine and it has refused to start on me three times. I had the battery taken out & checked, auto repair said it was ok, put it back in and jumped it and it cranked, ran for three weeks. 2nd time was after a long day and was leaving choir practice at 9pm and it wouldn't crank, lights came on and window rolled down, car said nothing, got it towed to mechanic the next afternoon cause it still wouldn't crank. The mechanic put a used starter on it, stating only problem he saw. It cranked but the horn wouldn't blow after that (it was weak anyway) Two weeks later it did the same thing. Mechanic put brand new starter on this time and when cranking it, it didn't the 1st time, then hesitated before starting the 2nd time. He says it may just need a new battery. It has a 26R size battery in it. Is this the correct battery or could it be something else?

ANSWER: Hi MsRC,
The battery size you have is correct. How close to the end of its warranty life is it? Check the label on the battery for that life guarantee and also the punch out code for when it was installed.
I would check out what is called the ignition-off draw current for the possibility that there is some electrical component that is drawing too much current when the vehicle isn't in use. You would need an amp meter for that, or the mechanic can verify that situation. It should run about 25-50 miiliamps normally. If more than that, then remove fuses, one at a time, to find out which circuit is carrying excessive current.
If the battery is reasonably 'young', the alternator charge warning light is not "on", and you don't have excessive ignition-off draw, then I would expect the new starter motor to turn over the engine reliably.
Distinguish that issue from a 'no start' of the engine, even though the starter motor is working properly. Let me know if that is the problem.
Please read the PS (below) and respond to it.
Thanks,
Roland  

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QUESTION: Can I do that myself or do I need special tools?

Answer
You will need access to a milliamp meter. Remove the - post clamp at the battery and insert the two leads from the meter between the post and the clamp. Set the meter to read 100 milliamp full scale and see what it reads.
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