A/C blows on every setting but one.

[Bronson]

Hey everybody. I inherited my grandfather’s 1996 K1500 Silverado extended cab with the 5.7 and 353,715 miles on it (as of right now). I have been in the process of restoring it for the past year or so. When I first got it, the A/C only worked on high. I replaced the resistor and that fixed the issue. After a few weeks the blower setting right under high quit working but all others worked fine. Since then, the resistor has failed 2 more times. Today I replaced the resistor and blower motor hoping that would solve the issue of the resistor failing. However, the blower setting under high is still not working. I’m wondering if it may be a bad switch but I really don’t know. Does anyone have any other ideas? Any help will be appreciated. Thanks in advance.