Where are the the heater core and the control valve on this vehicle? on 1991 Mercedes-Benz 300SEL

The car was chilly on the trip south from Idaho in zero degree weather. The coolant is up to level. The blower is magnificent. The heater hoses are hot. The engine temperature is 85 degrees centigrade. It seems that either a door is closed or a control is stuck somewhere within all the wrappings.

Asked by for the 1991 Mercedes-Benz 300SEL
I am not sure if this car has a heater valve, so follow the heater hoses up to the heater core to locate it. Often the climate control head goes out on this vintage Mercedes, so that is something to check. As far as dealing with the heat control door operation, that can be a huge job, you have to remove the dash to get full access, which is a 10-12 hour job for a Professional Tech.
Thank you! Is the climate control head the electronic temperature roller with numbers on it in the center console? I have not dropped the blower motor from under the dash yet. Perhaps then I will see the heater core and hose connections that disappear from sight as rubber hoses entering a multifaceted firewall.