Generally, I try to separate it out. There have been a few times where I absolutely loved an author, only to research them and read their interviews and find that they're an asshole, or a bigot. It's disappointing.
I'm not sure I can think of a time where the reverse happened, where I looked up an author and afterward admired them more, or felt a deeper connection to their work. So I generally avoid it.
The only time I didn't separate was with Lemony Snicket, and that's because he's a part of the books he wrote. Aside that, I take the story for what it is.
I think ^neurotype is absolutely correct in saying that it is an important factor in nonfiction.
For more modern fiction, it matters a lot less for me. Say 50 years back or so. But the farther back you go, the harder it can be to understand context, so for classics and older material, I find knowing about the author can help a great deal.
One modern exception for me has been John Green. I was a fan of his vlog for a long time and only picked up one of his books because I liked his videos. I didn't really enjoy it( I think I would have if I was 10 years younger) and normally I would never have tried another. But I heard lots of good things about his new one so I picked it up and it is on my shelf waiting to be read. I would never have done that if it had been an author I didn't know much about.
I think knowing something about the author's life can in some cases enhance understanding of the work. Like being aware of Dostoyevsky's shaky upbringing, imprisonment, and conversion; it informs much of how we read his work. Or knowing about Gide's marriage and time in Africa. Melville's sea voyages. The lives of the Brontes. So on and so forth.
Of course, that is not the only way to read the work, or even the primary way to read the work. Better to focus on the text itself, then let all that other stuff provide context for the reading. It is sometimes important also to not constantly think about how so-and-so was sexist, racist, hated Jews or whatever. Sometimes not knowing anything about the author is helpful in this way. But I don't know, I am curious and if I like a writer or a work enough, I generally want to know.
I agree with the others: I frequently don't know that much about my authors when reading them. Even if I do, it usually doesn't hurt my feelings about them. Phillip K. Dick was a little...out there...but a fascinating writer, and that overrides the rest. Ted Sturgeon's writings sometimes advocated for incest and other practices that I do NOT tolerate, and that makes it tough to respect him as much, though I find I can approach his better works without remembering this fact.
Well, he wasn't perfect, but I agree that he has nothing criminal or cruel to forgive. His kids and wives seem to have made their peace, and that is a good sign.