How do you replace the Fan Speed Switch on a NuTone 3090 Range Hood?

SOURCE: Broken light switch on a Nutone

The Black 120vac Line In wire goes into "L". The Black wire goes into "2". The Red Wire goes into "3". When you install the switch, the Red and Black wires will be on top of the switch.

SOURCE: need manual

See http://www.broan.com/ImageLibrary/broan/pdf/InstallGuides/626978B.pdf
and download your manual

Bob

SOURCE: the fan and light switch are not working

I would begin by checking the electrical panel as the circuit breaker or fuse that sends power to the hood may have kicked or blown. If that is not the problem open up the wiring box in the hood. It is unlikely that bvoth switches would have gone bad at once.

SOURCE: noisy fan or motor?

HI. The most common issue here will be with a loose motor shaft. This is the part that the fan blades are mounted on. When this occurs, the looseness will cause the motor, and shaft to wobble, thus, causing this noise you here at high speeds. The wobble is less violent during the slower speeds, so it is not loud, in this case.

The second issue will be a warped fan blade. This will cause the fan to rub against the shroud, thus, creating the noise, as well.

If the shaft is loose, or bent, the entire motor will need to be replaced. Now, if the fan blade is warped, you can, simply, unscrew the blade from the shaft, and replace it(on most model)

SOURCE: Nutone WA6500 range hood fan motor noisy

We have the same product, 18 months in use and the very noisy motor has finally seized up. I contacted the manufacturer and was advised that I need a new motor, motor mounting bracket and fan rotor. The agent was not able to quote me a price for the parts but stated that even though my 1-year warranty had expired, if I faxed them a copy of the original sales reciept they could possibly send me the parts for free under the original warranty agreement. I've done as they asked but haven't received a reply as yet. After reading about all the problems with this product I'm tempted to dump the whole unit and try to find another manufacturer that has a reliable and QUIET range hood.