Inside Unit (Air Handler)

There is significant bacterial growth on my the fins of my blower wheel.

You will need to remove as much growth as you can, disinfect, install or add a UV light to prevent further contamination, and have duct cleaning to remove the growth from your ductwork.

My evaporative coils are leaking refrigerant.

A leak test will determine whether you have a refrigerant leak in your evaporative coils. 

If so, you will need to replace the coils.

My fan runs nonstop even when the thermostat calls for the unit to shut off.

You may have a failed blower motor, which needs to be replaced.

My inside unit is making strange/loud noises.

You may have a failed blower motor, which needs to be replaced.

My plenum (see above) is filled with dust.

You will need a duct cleaning.

The insulation on the inside of my air handler is soaking wet.

You will need a water remediation, which entails removing all of the old insulation and replacing with new insulation.

If you do not, you will have lots of bacterial growth.