2000 Buick Regal heater only blows warm air with temp set set on 90. AC works fine and automatic controller sends air to all selected discharge points, just doesn't get hot like it should. Both hoses in engine compartment get hot so thinking it has good flow. Thanks.
A few things will cause "just warm" air.
There's going to be an air diverter/mixer box that mechanically moves to mix cool air from outside and warm air from the heater core. You can normally hear this move if you listen and cycle the controls from cool to hot.
You say both hoses feel hot, and that's a basic test, but if the heater core is mostly clogged or the thermostat in the engine is stuck just a little, it may still feel hot, but not be moving enough water to give hot air.
Does the car have a temperature gauge on the dash? If that shows hotter or cooler than normal, the thermostat could be sticking. If the engine temp seems ok, there's still a chance of the heater core being partially or mostly clogged.