I know the basics of what an engine does and how it works, but everything, it seems, has its own supplemental systems that help everything run. Vacuum is one of those systems that I have little knowledge on. That being said, I have a few parts here that I don't know exactly what they do, or if they are crucial to proper operation. I believe that this is a coolant temperature override "switch". It is obviously broken. What does it do? Any source for a replacement? I've looked on the net and only found one thing similar to it... It seems to go to a contraption mounted by the coil. Any idea what that does? Picture below with a red line showing the route. Next is the limit fill valve, as named in the TSM. It is for the vapor recovery system. Any source for it? Is it just a check valve?