My Dad and I were changing the rear diff fluid today and I noticed this black box above the spare tire. Its not hooked up and I have no idea what its for. Anyone know? Should I hook it up?

 

Canister purge solenoid? Is there an electrical connector on it?

.

 

Part of the emmissions filter system
could be/go to the carbon canister.. could be a CO sensor..
if you have no checn engine lights.. at this point dont worry about it

 

It's your canister purge solenoid or also know as charcoal canister it should be hooked to your gas tank. I believe it is there to act as a purge valve to release unwanted pressure build up in your tank I would definitely worry about it if I were you

 

Thanks for the response guys. Yah its definitely the charcoal canister or purge solenoid. I think its safe though because both sides of the setup are not attached, meaning fumes from the gas tank just leave the tank, instead of building up pressure due to a stuck valve. I am extremely surprised I'm not throwing a check engine light though, especially since the charcoal canister is part of the emissions setup. I may fix it at some point, I'm not too worried about it now though. I've had the truck for three years. I think I would have had any issues regarding safety by now if they were going to happen.