What it this vacuum hose?

[jff45]

It comes off the banjo on the vacuum pump. Yes, I know there's a broken tube on the banjo, it's the throw away 24v alternator.
It passes around the front of the engine and was cut off just above the pump.
I'm thinking it might be for the FICD that is usually on the firewall because a 2nd hose should then come back down to the pump.

I'll add a 2nd question because I can see them in that pic. There are 3 temp sensors there in the top left. 1 will be for the gauge, another for the glow plug system. What is the 3rd one?
The TB45 has 2, 1 for the gauge and the other for the ECU.

[jff45]

I've since learned that the 3rd temp sensor is for the EGR control unit.. so I can use it for something else.