get very little heat,w/blower on. Thermostat is Ok 190deg.coolant level OK ?? on 1999 Volkswagen Passat

Checked heater core temp.on hoses in & out and it seems same temp is hot evenly in and out.
with blower working heat-drops
Radiator liguid level OK.
Temp. control-knob & cable seems to be operating can hear damper changing position from cold to hot.
can't find a heater control valve... What can it be????

2 answers 1 comment
heater core clogged?
Got Milk?
Is the t-stat rated at 190 degrees or is the engine running at 190? Heater control valve may be inside under dash.