On an aside, it would be nice if guys like you would buy shop manuals for your 75 car, and send a few of us (and me) copies of the data so we can post it.
MyMopar does not have anything later than '73. Here are the aftermarket MyMopar wiring diagrams for '75
http://www.mymopar.com/downloads/1975/75DartA.jpg
http://www.mymopar.com/downloads/1975/75DartB.jpg
Here is the switch connector showing wire colors "in order". this SHOULD match your old switch, and the harness to the panel
From top to bottom the functions are
YELLOW........start
BLACK..........ACCESSORY
DARK BLU.....IGNITION RUN
BROWN.........BALLAST RESISTOR BYPASS
RED...............BATTERY POWER TO SWITCH
ORANGE.........LIGHTING (dash lighting) might be for shifter quadrant
RED................IGNITION BUZZER
(Bottom) RED...ambiguous may be key in light delay circuit
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