stevent72

I have a 2017 XL with the 3.5 N/A Engine and Manual (basic) Climate control. It's only 2 months old to me so I'm not completely used to it yet. When I have my heat on (most noticeably on High), I hear the blower occasionaly go back and from from what sound like high, to a lower setting. It's not when blue-toothed to the phone as that is normal. I'll hear it randomly sound like it goes full for a while then quieter then back full a little later. Has anyone experienced this?

Geom

Have 18 XLT 2.7 Eco boost and yes have noticed fan speed changes on its own (noticeable at higher fan speeds), not related to connected phone calls. Not sure what it is, thought maybe a filter clean cycle?

dantrigg

I have noticed it and I believe it is not actually a fan speed change. I can make it change sounds in an identical way if I switch back and forth between Fresh and Recirculation. I believe the truck is switching back and forth between recirculation and fresh without also changing the state of the recirculation lite.

I don't know why it is doing it but due to the sound changing in an identical way, I am pretty confident in what it is doing.

I hope someone else can explain why.

brg2015

This is exactly what it's doing. I don't have my manual in front of me, but it does mention this and explains why.

Edit: this is from the manual that I found online. It only talks about cooling, but I believe it uses the same principle to heat the interior quicker.

Note: Recirculated air may turn off automatically (or be prevented from turning
on) in all airflow modes except MAX A/C to reduce risk of fogging. Recirculated
air may also turn on and off automatically in Panel or Panel and Floor airflow
modes during hot weather in order to improve cooling efficiency

<-KJP->

Pretty sure it is normal, my current truck does it and my 2011 used to do that too.

slowpony46

Mine does that too. Sounds like the speed changes but I don’t think it actually does. I think it is moving the recirc door to help maintain the set temperature. I pointed it out to the dealer and they said it’s nornal. They say everything is normal though.

2015rubyFX4

Yup mine does it too. First time I head it i thought I was hearing things and I turned down the radio.. Now, I feel better

motsco

i get it also. sounds like blend door opens more and let’s the fan speed up and minutes later goes back. when it happens i hear a thump in the heater box.

Gordy49913

If you have the heat on in the truck, after the recirculation door shuts off, hit the button on the heater controls to open it again. Sounds just like the automatic feature.

lucky644

I hear it as well, but it isn't as loud/obvious as when I enable recirculation. It's quieter.

Reminds me of the noise my old truck made when the AC compressor was cycling.