Wiring headlight switch

I’m just now getting to the wiring of my A100 pickup. I have an EZ WIRING harness. I’m kind of confused about the terminals on the headlight switch. Attached is a diagram of the switch terminals. I know B1 & B2 are the power terminals, H is for the headlights, I think P is for park lights (front and rear), R is for taillights (I think), not so sure about I & D. Can somebody help me figure them out? Thanks, Steve. 8ED32954-CA8E-4495-9D94-8521FA00C5D7.jpeg