If both heater hoses are warm, that tells me the heater core is not cloggged and is functioning correctly. We'll assume the t-stat is still good. That pretty much leaves only one possible culprit - the blend door. Even though your '97 doesn't have A/C, it still has a temperature blend door, and that could be your problem. From the Ford Manual:
Temperature Control
The temperature blend door, located in the heater air plenum chamber, directs outside air to flow through the heater core for heating, or to bypass the heater core for ventilation. It is controlled by the temperature control **** of the heater control.
A heater temperature cable connects the temperature control **** to a cam which operates the temperature blend door. When the temperature control **** is at the COOL position, the temperature blend door directs outside air to bypass the heater core. When the temperature control **** is at WARM, the temperature blend door directs outside air through the heater core where the air is heated.
Positioning the temperature control **** in any position between COOL and WARM causes the temperature blend door to direct more or less outside air through or around the heater core for whatever proportion of heated or unheated outside air is desired.
Here's a related link that might help you:
https://www.ford-trucks.com/forums/5...ment-part.html