AC Fan / Blower on and off problem

I have a 2002 Avalanche 5.3L Z66. When I first start my truck, no air blows out of the vents. It doesn't matter what speed the fan is set on or if it is set to A/C or heat - no air blows out of any vent. The speed I'm driving has no impact. When I go over a speed bump the the fan comes on and air blows out of the vent as normal. If it's set to a/c cold air will blow perfect. I did just have the transmission replaced, not sure if they hooked something up wrong. This has happened extremely infrequent over the last couple of years. Now I have this problem every time I turn the truck on.

Is something loose or going bad? Thanks

RELAY?
Control Module?
Resistor?
Blower?

Should I check one of those before the others?

FIrst try disconnecting battery formin or so and then reconnect.
If that does nto fix then check relay by maybe swapping out.