Did you feel both heater hoses once the car is up to normal operating temperature?
If so, are they both HOT?
OK. If you have heat to the hoses (and therefore the core), then I suspect that the actuator (motor) for the temperature control is not working.
Here is the schematic and the "logical diagram" for where this actuator is.
The first thing I would do is check the HVAC fuse (with a test light of multimeter) and make sure it has power on both sides. If that is OK, I would look at and feel the actuator and check to see if it is moving when the temperature control is moved (with the key turned on). If not, then I would check for voltages at the connector to the actuator.
This is where the documentation gets strange, I don't remember what is correct on this particular model car. The service manual shows the actuator both under the hood and in the passenger compartment. I suspect it is in the passenger compartment, based on the procedure to replace it. So I will send you the procedure and you can let me know if this is not right.
Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Tighten the temperature actuator bolts to 1.5 N·m (13 lb in).
Here is another diagram that shows the location of the actuator inside the passenger compartment.
Here is the other diagram that shows the actuator under the hood.
Since you have the car with you, you should be able to tell pretty quickly which location is correct.
Please let me know what you find.
Take Care, Greg A.