heater does not get hot. Two hoses, one gets hot and one doesn't.What to do?

maybe your thermostat is stuck open need to be replace, check the blend door maybe not working or moving.

Symptoms of a restricted heater core. I had 2 yesterday with both hoses hot and the heater would not blow warm air. Had to flush the heater core on both vehicles and got rusty water out, and they both worked very well afterwards.

These use a hot water control valve, and sometimes the cable gets bad, and others the knob that you turn strips out and fails to control the valve. Check to see if the valve is being controlled while someone else turns the heat control knob.