In Ford Ranger
What could be the problem on a 1998 Ford Ranger if you have replaced the thermostat and checked it to assure proper installation and both heater hoses to the core are hot but no hot air is coming from any vent?
Answer . Is the coolant full?. Sounds like the heater core is plugged up try flushing your cooling system this may help if not the heater core will need replaced. Or there… could be a problem with the heat select switch or vacuum lines under the dash that control the heater door.. Answer . COULD BE THE BLEND DOOR ACTUATOR. OR BLEND DOOR INOP. OR TEMPSELECT SWITCH. Many of Fordï¿½s manual air conditioning systems use an electronic blend door actuator (motor) to control the temperature of the air entering the passenger compartment. The temperature knob on the A/Cï¿½Heater control panel is a variable resister (potentiometer) which varies a voltage signal to the motor. This signal determines blend door movement. Complaints of temperature always hot, cold or not changing as the temperature knob is rotated will be caused by one of four problems: 1) bad actuator; 2) bad potentiometer; 3) open or shorted wire(s); 4) broken door.. See this site for troubleshooting procedures. http://www.4s.com/fourseasons/tech_tips/tech_tips_english/AB356_Ford\'s_Blend_Door_Actuator_02.pdf. Answer . I had the same problem with my 1998 Ford Ranger and the accumulator hose was disconnected. Replace the hose and it is functional once again. (MORE)