1999 Ford Taurus heat problem

TEST C: ELECTRONIC BLEND DOOR ACTUATOR DOES NOT OPERATE OR OPERATES INTERMITTENTLY
Check Electronic Blend Door Actuator System

Ensure engine is at normal operating temperature. Set A/C-heater system to MAX A/C. Turn temperature knob to full cold position. Check for cool air discharge. Turn temperature knob to full hot position. Check for hot air discharge. Vary temperature knob setting. If temperature changes with knob adjustment, system is operating properly at this time. Check for intermittent condition. If temperature does not change, go to next step.
Check Electronic Blend Door Actuator System Fuse No. 6 (15-Amp)

Check fuse No. 6 (15-amp) in instrument panel (I/P) fuse panel. If fuse is okay, go to next step. If not, replace fuse and repeat step 1) again. If fuse is blown, repair short to ground in Orange wire or Light Blue/Black wire. Retest system.
Check Electronic Blend Door Supply Voltage

Detach blend door actuator connector. With voltmeter, check for battery voltage between Light Blue/Black wire connector pin and Black wire connector pin. If battery voltage is present, go to next step. If battery voltage is not present, repair open or short condition in Light Blue/Black wire and/or Black wire. Retest system.
NOTE:A quick check of blend door actuator can be done by connecting a replacement actuator and jumper harness to connector. Operate system and watch for proper blend door actuator operation.

Check heater hoses they both should be hot
if yes then I would suspect blend door and it need to be checked and or replaced
1.Disconnect negative battery cable. Remove right lower console trim panel from instrument panel. If equipped with center console, remove right, front side panel from console. Disconnect A/C electronic blend door actuator connector from actuator. 2.Remove 4 screws retaining A/C electronic blend door actuator to heater/evaporator housing. Remove A/C electronic blend door actuator.
To install, reverse removal procedure.

if not heater core need to be flushed
WARNING: NEVER REMOVE THE PRESSURE RELIEF CAP UNDER ANY CONDITIONS WHILE THE ENGINE IS OPERATING. FAILURE TO FOLLOW THESE INSTRUCTIONS COULD RESULT IN DAMAGE TO THE COOLING SYSTEM OR ENGINE AND/OR PERSONAL INJURY. TO AVOID HAVING SCALDING HOT COOLANT OR STEAM BLOW OUT OF THE COOLING SYSTEM OR DEGAS BOTTLE, USE EXTREME CARE WHEN REMOVING THE PRESSURE RELIEF CAP FROM A HOT COOLING SYSTEM OR DEGAS BOTTLE. WAIT UNTIL THE ENGINE HAS COOLED, THEN WRAP A THICK CLOTH AROUND THE PRESSURE RELIEF CAP AND TURN IT SLOWLY UNTIL PRESSURE BEGINS TO RELEASE. STEP BACK WHILE THE PRESSURE IS RELEASED FROM THE COOLING SYSTEM. WHEN CERTAIN ALL PRESSURE HAS BEEN RELEASED, PRESS DOWN ON THE PRESSURE CAP (STILL WITH A CLOTH), TURN AND REMOVE PRESSURE RELIEF CAP.
Engine cool
lower the coolant level
Locate the two hoses running to the heater core
disconnect them at the engine side leaving hoses connected to heater core throw the firewall
use garden water hose and compressed air if possible
run the water and follow by air throw one side and out the other and vice versa
do that two to three times watching what leaving the heater core you are looking for the good flow and clear water to run throw
good luck