My 2004 PT Cruiser (50K miles) starts in the morning, but recently has been totally dead when I come out of work in the afternoon, or have left it for several hours (usually in the heat of the day). This has happened 5 times in the past two weeks. I replaced the battery this Friday afternoon (it had done it once again), and it ran fine that evening. It also started without difficulty on Saturday AM, but I parked it all day while I was on a bus trip to NYC. When I came back that afternoon, it was once again without any power at all. When it is jump-started, it fires right up. This morning (Sunday) it started again, without any problem. Apparently, the battery is not the problem.
One other thing, about a year ago, the CD player began to act up, with CDs starting to skip after playing for maybe 15-20 minutes. I don’t know if these issues are related, but thought I should mention it.
I suggest you have a shop check the electrical system for a current drain as that appears to be the problem. If that isn’t the problem then they need to check for a problem with the wiring to the main accessories. Look for an intermittent connection from the battery.
The multi-function switch on the left side of the column has a well-known problem in PT Cruisers equipped with fog lights. The fog lights will come on and stay on and will drain the battery. If your car is equipped with fog lights, check to see if the lights are on after you shut off the car. If so, that’s your problem. A temporary fix is to pull the fuse for the fog lights, but the ultimate fix is to replace the multi-function switch.
If it’s not the fog lights, it could be the electric fan switch is sensing a need for cooling and turning on in the heat of the day. The sensor may be faulty and replacement might be all that is needed. Fans consume quite a bit of electricity and could easily drain a battery. Or maybe it’s that refrigerator you have plugged into the cigarette lighter? 