2003 Hyundai Santa Fe 4-Cyl 2 wheel drive intermittent starting problem

Current problem:  I was not with the car when it would not start or crank in the late afternoon, it was a warm day, about 90 F.  The battery is about 6 months old and is good. The tow truck driver came out and tried to jump start the car but that did nothing.  The car was towed home. I arrived home after dark, so I went down in the morning to see if I could determine what he problem is. I put the key in and turned it, the Hyundai started right up. This is not an overfill vapor canister problem. My question is:  Where and how do I look for this intermittent problem. Not the starter, alternator, or battery. 
   History:  I bought my 2003 Hyundai Santa Fe 4-Cyl 2 wheel drive new.   I am not a lover of Hyundai. They used too many cheap parts and the service at the dealer was very suspect. Regarding cheap parts: The dash controls module, ac,fan etc,  had to be replaced under warranty.  The female seatbelt receptacle on the driver’s side falls apart and has been replaced twice (at 50 K miles under warranty and 100 K miles at my expense).  The electric door locks do not work on hot days less than 50 K miles.  The dealer acknowledged the problem and replaced the solenoid, but that did not fix the problem. I think that the wire size from solenoid to battery is too small.   The chrome plating on the plastic door releases flaked off at 60 K, and cut our fingers, (dealer won’t replace).   Now I have an intermittent starting problem.