2003 Mitsubishi Eclipse Question: normal idle speed engine dies under electrical load

V6 engine (95,000 miles)just recently started dying at stop lights when idling with A/C on you roll-up power window(s) or increase the elerical load,
Alternator output drops to about 11.7 volt on shop meter, engine idle drops to about 600 RPM, engine starts to loap, and dies. Will restart easily. Already tried new alternator and battery, seems to search for more idle RPM's. Maybe Electronic Control Module ? Maybe an electrical short in wirring ?