Circuit 904 (LG/RD)
WARNING: This page is about a different car, the 2005 Ford Pickup, 2004 Ford Pickup, and 2003 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
This is GEN COM circuit. The PCM determines the optimal voltage set point for the charging system and communicates this information to the voltage regulator on the GEN COM circuit.