2015 GMC Sierra 1500 wipers, windshield & visibility problems

Headlights - low are dim and not much side visibility. Traveling on rural back roads at night is dangerous. Deer walked out in road and I was not able to see in time. Second deer I hit with this truck, only hit one other deer in my life.

Vehicle was stationary on the street, parked. I entered it, and turned on my front and rear defrosters with the setting on "hi." I turned around and verified that my vehicle had not been hit nor was any damage at all apparent to me. At some point as I sat there with the car idled and the heated air reaching its maximum temperature, I began to smell some foul smell in the cab that I believed was exhaust entering the cabin. I rolled down the window.