Electrical problem
2003 Saturn Ion 4 cyl Two Wheel Drive Automatic 125000 miles

When I have my parking lights on and my car is in drive, my lights flicker on and off. When I have my lights on regular or fog lights on in park, they do not flicker. I don't want the service dept. to tell me some crazy outrageous lie and charge me alot to fix it. I would kind of like to have an idea of what it is and approx. cost to fix it if possible. Thanks.