My brother and I are working an a 1996 Stratus for a family friend who is going through hard financial times due to health issues. The heater in the car works fine (blows hot air) but it is stuck in vent mode. The defroster or the floor heat mode does not work. Is the mode selection knob attached to a cable or is it electronic on this vehicle? If it is electronic, any thought as to the cause of the other heater modes not working. Thanks