2001 Chevrolet Suburban 2500 LT 8 Cyl 8.1L
even though the heater dial is in the off position, the vent system is still allowing heat to blow through
the air conditioning has not worked for over a year now- but this problem has only began this past month.( the car has a problem with the coolant system, and we add a small amount of fluid each week, as the car leaks fluid on the pavement).
The heat still making it through can be your blend air door not working. The fluid could be your heater core, but that depends on where the leak is under your car.