Ford 2000 Expedition no heat
2000 ford expedition 5.4L, no heat front or rear. AC works good. Flushed cooling system October 2016 at 105K miles. Soon after the flush no heat--heat for 15-30 seconds then cool air. Replace thermostat but still no heat. Repair shop said could be blend door. I started the Dorman fix but in the process discovered that the actuator and the blend door are working. Nevertheless, cut through the glove box and heater box and can see that the blend door is working. Can feel the heater core through the cut out. Heater core gets warm to the touch but not to hot to touch. AC works good, but when switch to heat only get some heat for 15-30 seconds. When I feel inside the heater box it seems to me that the AC never turns off ie... always blowing cool air. What should I do next? Is there a temp control sensor that is not working to turn the cool air/ac off? Should I reverse flush the heater core? Thx"