My new 2004 Legacy has the A/C interlocked with 2 setting on the heater, 1)defroster AND 2) the defroster/foot outlet.  To save fuel, I would like to disable the A/C when the defroster/foot setting is selected.  In my 1996 Outback only the defroster setting was interlocked.  Most of the time the widshield stayed clear with the defroster/foot setting.  Is there a wiring diagram available? 
Thank you