The issue with your Irvine slow rise roller shade in the Thor motorhome likely relates to the internal spring tension or the absence of a proper locking mechanism on the bottom. Since the spring appears intact and not broken, it may be necessary to replace or adjust the spring to restore proper function. You can use the Elkhart RV Parts Quick Spring Finder tool to identify the correct replacement spring for your shade. Additionally, check if the shade’s bottom stop or locking component is missing or damaged compared to the working shade. Elkhart RV Parts offers a wide selection of replacement springs and shade parts compatible with most RV roller shades, including slow rise models. For best results, measure your shade and consult their RV Shade Designer or parts collection online. This will help ensure you get the right components to restore the locking feature and prevent the shade from rolling up prematurely.