[Vwdiesel] Vanagon Part X: Radiator Questions?

[jon]

Now that my fuel tank is clean, and the Van is running well, it's time to
look at other problems:

The previous owner put a manual switch in for the radiator fan. For me,
it's not a big deal to notice when to turn it on. But, my wife says "what
temperature guage", if you see what I mean. So, I want to restore the
automatic thermostat operation. I understand the thermostat is on the
radiator somewhere. So, here are my questions:

1) How does one access this switch?
2) Is there a way to test it out of the engine?
3) Why would the PO do this?

And off this topic:

4) Also, I have an electric fuel boost pump at the fuel tank. Is there
anything wrong with having this pump run all the time when the engine is
on?

Thanks!

Jon