shivering

My daughters 93 Subaru Impreza will not emit any heat from the heater. It just blows cold air. It runs fine and does not overheat. Anyone's help would sure be appreciated. Thanks

Checked the heater pipes coming from the water pump for blockages?

Maybe the connectors on the knob broke or something snapped behind the paneling. Does it feel loose when you turn the dial from cold to hot?

Thinking back, there is a rheostat block which controls the heater unit behind the dash, it's about 1.5 square of perforated steel with various resistor wires inside. I've had one of those go bad and the heater stopped working.

It's about a $40 part and not terribly difficult to replace.