What are the numbers on the plastic body? Those will help with identification. Do you know the brand of your dash air? Winnebago used 3 different brands through the years. The most commonly used was Evans Tempcon. That company filed bankruptcy in Dec. 2022 and closed the doors in Jan. 2023, but parts are still available.
Here is the Evan Tempcon service manual, hope it helps.
__________________ 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member,FMCA. "We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert the Constitution." Abraham Lincoln