Chrysler Repair: Pacifica wont start

Question
My wife has an 05' Chrysler Pacifica. It sat in a parking lot for a couple days and it's been cold out. I went to go start the vehicle and it was trying to turn over but wouldn't start. So I decided to jump it, still nothing. So I went and picked up a new battery had them test the old and it was shot.  Put the new battery in and made sure the terminals were clean. Put the key in and everything lit up the way it should but the vehicle would only make one click noise when the key was turned. Any ideas?

Answer
Hi Ryan,
There are two items that 'click' when you try the start position: first there is a soft click from the starter motor relay in the power box under the hood (possible not noticeable) and then there is a loud click from the solenoid switch on the starter motor itself in response to the relay having done the soft click (closing of the circuit to activate the solenoid switch).
If it is a loud click and the starter motor doesn't crank, but it did crank before the old battery gave up, then I wonder if the new battery clamps are clean and tight, and if they are then I would wonder if the starter motor may also be on the decline. You could try tapping on the side of the starter motor with a hammer while a helper tries the key which sometimes will "jar" a poor connection inside the starter's commutater/brush interface.
Once you get the starter to respond then see if it will start.
In the meantime, turn the ignition key; "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window of the cluster to see the mileage reading to be replaced by a 4-digit number prefaced by a P. That would be a fault code that could explain why the engine didn't catch and run when the starter motor was working. Let me know the number(s) that appear.
Please read the PS below and respond to it.
Thanks,
Roland