My AC fan sounds like it is surging.

[Tozan]

With the AC on high and the face vents on I get a surging sound like the fan is going faster or slower but, the air coming out of the vents remains the same. The volume of air coming out of the vents does not feel as strong as it did in the past either.

It also takes much longer to cool down and is not getting as cold inside as it did in the past. Temps here right now are only around 100. Yes, even at a hundred it normally cools down pretty quick since I have 13mm of sound / thermal insulation in all the panels and the roof.

The system is full and AC gauges are reading normal...

I do several thousand miles of off road trails in dusty conditions and I do have a cab filter that is about a year old. (I did order a new filter but, I have not installed it yet) I am hoping that is my problem...

What do you experts think?

 

[drakon543]

could be the bearings going bad in the blower motor.

 

[OR VietVet]

could be the bearings going bad in the blower motor.

If not the blower motor itself, it could be this: https://www.rockauto.com/en/moreinfo.php?pk=8369520&cc=3015551&jsn=1725

 

[Tozan]

It isn't a bearing noise it sound more like a vent or something is not working properly.

 

[OR VietVet]

Can you feel the difference in the air flow velocity? Or is it just a sound?

 

[Tozan]

Can you feel the difference in the air flow velocity? Or is it just a sound?

No air flow change just a change in sound.

 

[Doubeleive]

No air flow change just a change in sound.

mine does that sometimes also, I went ahead and preemptively bought a blower motor resistor in case it decides to crap out but the resistor appears to be fairly heavy duty on these trucks compared to the nbs so I don't know if it is that or not

 

[PG01]

With the AC on high and the face vents on I get a surging sound like the fan is going faster or slower but, the air coming out of the vents remains the same. The volume of air coming out of the vents does not feel as strong as it did in the past either.

It also takes much longer to cool down and is not getting as cold inside as it did in the past. Temps here right now are only around 100. Yes, even at a hundred it normally cools down pretty quick since I have 13mm of sound / thermal insulation in all the panels and the roof.

The system is full and AC gauges are reading normal...

I do several thousand miles of off road trails in dusty conditions and I do have a cab filter that is about a year old. (I did order a new filter but, I have not installed it yet) I am hoping that is my problem...

What do you experts think?

What does it do when you hit the recirculate button? .....sounds more like this is the issue. Is the rear on too?

 

[Doubeleive]

What does it do when you hit the recirculate button? .....sounds more like this is the issue. Is the rear on too?

I don't know about his but when mine does it, it sounds just like he said the fan "sounds" like it is surging like going slightly faster for a few moments, not long enough to feel any difference but I can hear it, it does this without touching or changing any controls, I have checked it with the tech2 and there are no errors or codes. mine however is the digital control and it could very well just be it self adjusting to the temperature requested. when I hear it the sound comes from the front I don't hear the rear doing anything different I usually have the rear fan turned down enough so that I can't really hear it, once the fan is up to a certain speed the air sound thru the headliner vents is somewhat annoying so I adjust it down a little. could be the resistor not really sure but I bought one anyway so if it gets worse or dies I have a quick fix handy.
**and my recirculate button is usually on all the time, if it was the recirculate actuator going goofy it would probably give me a dtc.

 

[PG01]

I don't know about his but when mine does it, it sounds just like he said the fan "sounds" like it is surging like going slightly faster for a few moments, not long enough to feel any difference but I can hear it, it does this without touching or changing any controls, I have checked it with the tech2 and there are no errors or codes. mine however is the digital control and it could very well just be it self adjusting to the temperature requested. when I hear it the sound comes from the front I don't hear the rear doing anything different I usually have the rear fan turned down enough so that I can't really hear it, once the fan is up to a certain speed the air sound thru the headliner vents is somewhat annoying so I adjust it down a little. could be the resistor not really sure but I bought one anyway so if it gets worse or dies I have a quick fix handy.
**and my recirculate button is usually on all the time, if it was the recirculate actuator going goofy it would probably give me a dtc.

Right, that’s why I askeded.....
You need recirc on all the times because of all that damn ash and heat.....