Defogger problems of the 1998 Chevrolet C/k 2500

Passenger side defroster does not work. I was told this was a normal characteristic of the truck and it was not a problem by bufford ward Chevrolet in quincy illinois 62301. It is nearly impossible to see out of the passenger side of my windshield when the weather is bad or there is ice on the windshield. There are vents for the defroster and hardly any air comes out of them. The drivers side works fine. I checked two other 1998 Chevrolet trucks on the lot and they both had the same problem. I feel this is very unsafe. I am an illinois state trooper and I handle many accidents because of obstructed drivers view. I would appreciate your earliest response.