The unit in our car was bad so we replaced it w/ a NOS unit. However, I was curious what was it was like inside to see if they could potentially be repaired. Here's a picture for anyone else that's interested in seeing what's inside. In the case of ours, all the little nibs for the vacuum connector were broken off. To me it looks like it got contaminated with oil or grease which caused the plastic to weaken. Inside there is a small rubber block with a recessed "H" pattern on it that redirects the vacuum. On ours, it was clogged up with some kind of black gunk. So even before the nibs broke off it probably wasn't working correctly. However, the rubber block itself still felt soft and pliable. If the nibs weren't broken off, it probably could've been cleaned up and reassembled and (seemingly) would work.