2002 Dodge Neon Electrical Problem

My son's 2002 Dodge Neon is having some sort of electrical problem. My mechanic had it for three days and cannot figure out what it is. Not the starter or ignition. Now the car is at the Dodge dealer and they will look at it tomorrow possibly. Just wanted to see if anyone had any ideas as to what the problem could be - I'd like to know in advance what questions to ask as far as diagnostics. The car only has about 50,000 miles on it. Maintenance on the car is current. Any help is appreciated.

Jackie