Furnace installed in 1996.. recently purchased home... what type of maintenance is required for this furnace? What components need oiled/greased? Humidity control seems not to be working.. corroded parts on outside of furnace control.

I would try contacting Bryant/Carrier and see if they can get you an installation guide that may include all the things that need annual maintenance such as: fan lubrication, temp sensor cleaning, coil cleaning if you have one, routine HSI replacement depending on type. Longer term you may need heat exchanger cleaning, burner cleaning and adjustment, gas valve adjustment, etc.