Dash air question

[H20 Toie]

2008 American Tradition 42F
When i turn the fan switch on the dash air each click i can notice more air until the last one.
I would expect a lot more air when its turned to full.
The motorhome shop where i took it can't find anything wrong. what should i check?
also any one know of a shop around Los Angeles that would be a good choice to have it checked out at?

[Gary RVRoamer]

I think you should find another AC owner and compare fan air volume before spending money to fix something that probably isn't broken. The dash air fans in my '04 seem to produce mostly on speeds #2 & #3. #1 is almost nothing and #4 is noisier than #3 but doesn't seem to move much more air. I suspect that the air ducting and/or inlet door simply doesn't let much more air into the system, so increasing the fan speed only makes it spin faster but there is no more air to move through the system.