If you haven't checked your TV's Cabin Air Filter in the last year or so, I highly recommend that you do.
I have a 2016 GM 2500HD and checked mine a couple days ago........ couldn't believe the trash (twigs, leaves, bugs, etc.) stacked in/on top of the filter..., looked almost like a nest
In the process of removing my filter the debris build-up on top of the filter fell into the blower motor below the filter housing, thus I had to remove the blower motor to empty it out.
I didn't take any pics of my filter/motor R&R, but the following videos will walk you through a 2014 - 2019 GM truck cab filter, and/or blower motor R&R.
Cabin Air Filter R&R.....
Blower Motor R&R......
2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (Strait-Line)