Heater blowing cold - 2011 Expedition EL XL

[SouthwestORV]

Good morning, friends. At the outset I will state that our 2011 Expedition EL XL has been the best vehicle we've ever owned in every way - comfort, capability, and reliability. It now has 203,000 miles on it, all original. I haven't even replaced the spark plugs or coil packs.
To the issue at hand - two days ago I started the truck to move it, and it was making a loud plastic popping sound from behind the dash. The sound would happen for moment, then stop for a moment, then repeat. I never timed it but I'm going to guess it would pop continuously for 20 seconds, then pause for 20 seconds. I took the time to fiddle with the HVAC controls and nothing affected the popping sound. The sound has not repeated since Friday, but now the heater does not blow warm/hot up front. A/C does seem to work and blow cold. Warm air DOES blow from the rear AC when I turn on heat to the rear. The front controls DO work from the standpoint of switching where the air is blowing, defrost, vents, feet etc. But it blows cold. The problem appears to be isolated to this: no warm/hot air will blow out of the front system.
Any ideas as to what the problem is and how to fix it?
Thanks in advance. We love this truck and want to keep it going.

 

[99WhiteC5Coupe]

Good morning, friends. At the outset I will state that our 2011 Expedition EL XL has been the best vehicle we've ever owned in every way - comfort, capability, and reliability. It now has 203,000 miles on it, all original. I haven't even replaced the spark plugs or coil packs.
To the issue at hand - two days ago I started the truck to move it, and it was making a loud plastic popping sound from behind the dash. The sound would happen for moment, then stop for a moment, then repeat. I never timed it but I'm going to guess it would pop continuously for 20 seconds, then pause for 20 seconds. I took the time to fiddle with the HVAC controls and nothing affected the popping sound. The sound has not repeated since Friday, but now the heater does not blow warm/hot up front. A/C does seem to work and blow cold. Warm air DOES blow from the rear AC when I turn on heat to the rear. The front controls DO work from the standpoint of switching where the air is blowing, defrost, vents, feet etc. But it blows cold. The problem appears to be isolated to this: no warm/hot air will blow out of the front system.
Any ideas as to what the problem is and how to fix it?
Thanks in advance. We love this truck and want to keep it going.

One of your HVAC actuator motor gears have stripped - causing the heat/cold blend door to remain at the “cold” position.

There are numerous posts on this forum regarding the issue. You may want to do a search and some reading.

Some of the HVAC actuators are somewhat easy to replace. One or more are difficult and involve many hours of labor, and partial dash removal.

 

[GlennSullivan]

Im absolutely shocked your blend door actuators lasted 200,000 miles! My 2011 only has 67,000 on it and mine started failing at mid 50,000.

 

[SouthwestORV]

One of your HVAC actuator motor gears have stripped - causing the heat/cold blend door to remain at the “cold” position.

There are numerous posts on this forum regarding the issue. You may want to do a search and some reading.

Some of the HVAC actuators are somewhat easy to replace. One or more are difficult and involve many hours of labor, and partial dash removal.

Yes, I figured it was an actuator motor based upon my prior searches and reading. But I'm hoping someone can help me narrow it down to WHICH actuator.

 

[SouthwestORV]

Yes, I figured it was an actuator motor based upon my prior searches and reading. But I'm hoping someone can help me narrow it down to WHICH actuator.

Thanks.