heater core...

If it's clogged you may be able to remove it and take it to a local radiator shop to be flushed or re-cored.

The lever that controls the heat, hot to cold, works a valve in the hot water line. If it doesn't work, it causes the same effect and is more likely your problem. Check that first.

ok, well i will check on that, but how do i access that valve? thanks

I don't think this model has that valve. The heater core is like a $20 used part at a wrecking yard. Anyone from an 85 to 94 should work. Had plenty of Subaru radiators good bad over the years but never a heater core. Check the linkage down by the gas pedal. Make sure everything moves when the control buttons are pushed. I have seen several Subarus that had no heat only because a small plastic clip down there was missing.

There must be some valve that's closed. It's not likely that a heater core would be clogged to the degree that you would have the output hose be totally cold. Or maybe you have a defective heater control unit.