WHAT IS THE PROBLEM WITH MY HVAC CONTROL? ON MY 2003 SATURN L300.

You've covered the basics with fuses and relays, probably best to look at a workshop manual and get an overview of the system and then follow a wiring diagram for your car. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online

Sounds like you checked the basics, if power and grounds are good the a/c control unit itself might have gone out, this should be diagnosed to confirm as they are not cheap! Hope this was helpful. Ryan Mode Mode Automotive 858-361-4645