02 Century Blower

I have an 02 Buick Century that has been exhibiting issues surrounding the blower. At first, the blower would only work on the high range of speeds; this eventually changed and the blower would not work on any of the speeds. I replaced the blower motor resistor, which fixed the problem for a few days, however it reverted to not working at all. Replaced the resistor again, but the behavior did not change; the blower still did not work at all. What should I try next?