This one time I had an ML in with the following complaint.
"Customer states a/c is not blowing any air."
I tried it, and it made a sound like the squirrel cage had broken off and was grinding around in there.
I pulled the under dash panel, loosened the 3 screws, and when I pulled the motor down an avalanche of dog food filled the floor!
About 7 lbs worth.
I told the s/a this was no longer a warranty job, and had to spend over an hour cleaning dog food out of the heater case!
Can you imagine the smell that vehicle will have for the rest of its life?