Crew Cab, Thanks!!!Rear wiper switch if it's a Blazer, Jimmy, or Bravada. Air Bag switch if it's an S10, Sonoma, or Hombre. Crew Cabs and Base model Blazers will have an empty block off plate that the connector clips into, but doesn't power anything.
Since you're talking about 4WD, I'm assuming this is your crew cab, so it will plug into the blank panel that goes in the rectangular opening below the 4WD Switch.