What's this black box?

[BurnTheLight88]

I was under the Mounty ('99 5.0 AWD) and was looking for the fuel filter. Found it. But while I was looking, above the end of the tank closest to the rear, there is a rectangular black box. The only thing I could read on it was (<-- To Canister). It has a rubber hose connected to the side that the arrow is pointing to, but the port on the other end that looks like it should have a hose connected also doesn't have anything.

What is this black box, and should there be a hose connected to both sides rather than just one?

 

[my pos mounty]

If that black box is tucked up under towards the back of the truck where the spare tire is, it is part of the pollution controls. I had a check engine light come on a few years back and had to replace the whole thing. Its the evap canister, and if memory serves theres a solenoid that went bad on mine.
If it is not hooked up correctly, it will throw a check engine light with code.

 

[OneLever]

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