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Q: What is the problem when my truck only blows out cold air? Can I fix it myself? on 2005 Ford Explorer

My truck's heat will not warm up. It will only blow out cold air. If I drive the truck for a while with the air off, when I turn it on, there will be a little bit of heat for less than a couple of minutes and then gets cool again. I was told antifreeze - added it. I was told thermastat - replaced it. Now I am told the hot/cold switch is stuck on cold. I was told this is a quick fix, but there's a trick to it. Saw on internet it can be the blend door which can be accessed through glove box - didn't see it. I also saw that it may be the whole actuator needs to be replaced. Doing more research, the people with the issues with the actuator are having a clicking noise along with the straight cold or hot air. I do not have that issue. I just have no heat. Please help!
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Let me pull up my soap box. I'm 56 years old. I didn't have the power of the INTERNET untill the last 15 years. The forums are very helpfull out there, but you can waste alot of money untill your problem is properly diagnosed by a professional tech. Not all auto repair shops are rippoffs. Unfortunately finding the right repair shop can be a crap shoot. Now back to your problem.

Customer Concern: No heat from the heating-ventilation air conditioning system. The heater hoses are hot.
Tests/Procedures: 1. Attempt to reach the blend door actuator located forward of the glove box under the passenger side of the dash and place a finger on the actuator/door pivot. Feel for a rotational movement of the blend door actuator when moving the temperature control switch from hot to cold and back to hot.

2. If the blend door actuator pivot does not move, check for battery voltage on the Grey/Yellow (GY/YE) wire which is supplied by fuse 2.27 (10 amp) of the Central Junction Box (CJB).

3. If battery voltage is present on the GY/YE wire, check for voltage output on the Red/Light Green (RD/LG) wire, or the Red/White (RD/WH) wire feeding the temperature control switch. One of these circuits should indicate to be a ground, the other should indicate a voltage reading of about 10-11 volts. These circuits need to be checked with the blend door actuator connector plugged in.

4. Measure voltage on the Yellow/Light Green (YE/LG) wire while rotating the temperature control switch. This circuit should change between from about 0.5-10.0 volts as the switch is rotated full hot to cold and back.

5. If the YE/LG wire changes voltage as the switch is rotated but the blend door actuator does not move, replace the blend door actuator.

6. If there is no change on the YE/LG wire though the RD/LG and RD/WH wires show output voltage and ground, check the circuits for a possible open between the actuator and the switch before replacing the switch.

7. If there is no output voltage on either the RD/WH wire or the RD/LG wire with the blend door actuator connected though the power feed to the GY/YE wire shows battery voltage, replace the blend door actuator.

8. If the blend door actuator can be felt to pivot when the temperature control switch is rotated but there is no temperature change, either the heater core is restricted and will need replacement, or the blend door in the heater plenum is broken and the plenum would then need replacement.

You can also get any factory info concerning your Explorer for a whole year at Spend the $26.95. It is well worth it. Best of luck, Jim
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