My 2011 F-250 just started having a weird heater problem that I'm hoping someone
can help me with before I have to take it to the dealer.

My truck heater gets up to temp just fine but after cruising down the highway for about
15 minutes or so it starts blowing out cool air. I can turn the controls to defrost and back
again and it blows warm, not hot but warm then cool again.

Anyone else have this problem. It just started a couple of days ago. Temp gauges show normal temp also.

 

sounds like it might have something to do with the controller. I assume you have the EATC unit.

 

Yes I have the EATC unit.

I have also noticed that when I turn on the heated seat it seems that the blower
runs intermittently, then shuts off then runs again. When I turn the seat heater off, I don't
hear the blower noise. Not sure this is normal or not.

I just found this and may try it if it pertains to my year truck:

Electronic Automatic Temperature Control Module Self-Test
• The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A NGS tester must be used to retrieve these concerns.
• The EATC module self-test will detect concerns in the system control functions and will display hard diagnostic trouble codes (DTCs) in addition to intermittent diagnostic trouble codes for concerns that occur during system operation. The vehicle interior temperature should be between 4°-32°C (40-90°F) when carrying out the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
• The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated.
• To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.
• If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
• If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Improper Operation.
• To exit self-test and retain all intermittent DTCs, push the blue (cooler) button. The control will exit self-test, retain all intermittent diagnostic trouble codes and then turn OFF (display blank).
• To exit the self-test and clear all DTCs, press the DEFROST button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC control assembly will turn OFF (display blank) and all DTCs will be cleared.
• Always exit the self-test before powering the system down (system turned OFF).
• Intermittent DTCs will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.

EATC Hard Self-Test Faults EATC Intermittent Run-Time Faults NGS DTC Description
024 022 B1249 Blend door short
025 B1249 Blend door failure
031 N/A B1251 A/C in-car temperature sensor open circuit
030 N/A B1253 A/C in-car temperature sensor short to ground
041 043 B1255 A/C ambient temperature sensor open circuit
040 042 B1257 A/C ambient temperature sensor short to ground
050 052 B1261 A/C solar radiation sensor circuit short to ground
U1041 SCP invalid or missing data for function read vehicle speed
U1073 SCP invalid or missing data for engine coolant
U1222 SCP invalid or missing data for interior lamps

Note: While the above test is useful for diagnosis of suspected eatc related problems, many of the system outputs do not provide any feedback to the control head. Which means there could be numerous problems with your eatc system and you still get a "clean bill of health" from the self diagnostics. For instance, I did not recieve any error codes during the self test when I had the vacuum control block tubes & electrical connector unplugged, the air conditioner compressor request line not connected to anything, and the blend door actuator laying loose on a table without being attached to the plenum. If the eatc system were actually installed inside a vehicle like that, air would always flow from the defroster vents regardless of how the vehicle operator set the controls and temperature regulation would be nonexistent since the blend door could randomly flop around inside the plenum without any restrictions and the a/c compressor would never engage. Additionally, keep in mind that when set to the overide settings of either 60 or 90 degrees, the eatc head ignores temperature and solar radiation data and commands the blend door to either full warm or full cold position. So if you can't get heat in the 90 degree setting and cooled air in the 60 degree setting, your problem is NOT caused by the interior temperature, exterior temperature or sunload sensors.

 

run the test and see what you get. That would be the next thing to do.

 

Apparently that test does not work on my 2011 F-250. It did absolutely nothing. I did find out
that once it starts to blow cool air I can turn the temp down to 60 for a few seconds and then back up to 90 and it blows warm air again. I guess I'm hitting the dealership this week.

 

Took it to Ford dealer, found out it's a coolant leak behind the turbocharger.

Should be back in the saddle today.

 

Hi texas4x4,

How did the repair go at your dealership? Is your truck back at home now? Just checking in to make sure everything's back to normal.

Crystal

 

It was a leaking valve behind the turbocharger and they also found a leak in the radiator.
Had to order the parts and suppose to be ready tomorrow. Fingers crossed. My rental is
a Dodge Ram 1500 and that's killing me.

 

Thanks for reporting what is wrong. Hope it gets up and running soon.