HVAC fan grinding/surging

[optimusprime]

Noticed the other day that the hvac fan in the cabin has been surging (high then low). It is more pronounced when the fan is turned up high. Today I noticed it is making a grinding noise as well. Any ideas where I should begin my search?

 

[Doubeleive]

Noticed the other day that the hvac fan in the cabin has been surging (high then low). It is more pronounced when the fan is turned up high. Today I noticed it is making a grinding noise as well. Any ideas where I should begin my search?

could be the blower motor resistor but failure of them on this gen is rare they are pretty well made compared to previous generations.
could also be the blower motor it's self.
it "should" be one or the other.
I would speculate a small chance of it being a headliner environmental sensor causing the "auto" function to fluctuate.. (making the fan change speed based on temp readings)

 

[petethepug]

The hvac fan is not something that gets much talk on the forum. They’ve been pretty reliable.

If you want to check out the fan …

Here’s the resistor …

See what happens when you take the hvac off the auto setting. Does it still surge?

While you’re in there you can add the factory hvac activated carbon pollen filter kit too. It quiets the air cavitation sound down as well as well as keeps the interior cleaner.

https://www.rockauto.com/en/catalog...ditioning,cabin+air+filter+retrofit+kit,50209

 

[OR VietVet]

I can't remember whether it was a NBS, 2000-2006, or a NNBS 2007-2014, a/c complaint that was the same as this concern and it was the resistor causing the problem, even the grinding noise, and that surprised me.

 

[Joseph Garcia]

I would definitely inspect the motor's impeller to be sure that it is whole and clean.

 

[optimusprime]

Resolution:

I swapped out the blower motor resistor and the problem persisted. I put the original resistor back in and swapped out the blower motor assembly itself and it fixed the issue. Very simple and straight forward fix and it only cost me around $45. Thanks all for your help.

 

[Doubeleive]

Resolution:

I swapped out the blower motor resistor and the problem persisted. I put the original resistor back in and swapped out the blower motor assembly itself and it fixed the issue. Very simple and straight forward fix and it only cost me around $45. Thanks all for your help.

ya on this generation problems seem to be the blower motor more often than anything else had to replace mine as well. the resistors are much more beefy than the gmt800's

 

[petethepug]

Nice work. Take the $500 the dealer would of charged you and do something nice for yourself. Don’t forget to take the victory lap and edit the title to RESOLVED