2017 579 Pete Wipers only work when on the highest setting

[BrandonOlsen]

Have a 2018 579 Peterbilt and wipers only work in the 3 highest settings. If you use the lower setting it will go half way and just stop and won’t move until you turn it on higher setting. Sometimes it’ll go all the way then stops until you turn it on the higher settings. Replaced wiper motor. Didn’t do any good. Shop said they think it could need an update ? When I had looked at insite I had the latest update. This has been going on for a few months but with winter coming in hard I need my wipers to work normal . What should I be checking ?