is you vary well know Arizona can get really hot and for the cause of that people in hot climates can have trouble with any kind of battery. heat kills battery's. your phone for sure is still working but the battery is internally damaged. the average max temp for it to charge is 113°F until it wont charge at all and 140°F is the max until it starts to fail from working.
*This average can vary*
You said you left it in your truck all day which can turn your truck into a oven reaching around 180°F, Your going to have to tear down your phone and replace the battery and if i were you i would keep a spare just in case.