I just (ten minutes ago) used the following site
TRICO to look up the replacement blade for my Winnebago. They have an online catalog with motor homes, models and year listed.
Mine are carried locally by O'Reily Auto Supply. They are out of stock but will have them sent from their Salt Lake warehouse and I can pick them up tomorrow morning.
There are four part numbers available for your coach. Some are more expensive. The base unit shown in 25-280. They have an instructional video for each number.