What is this switch? What does it do?

http://i90.photobucket.com/albums/k264/jhong1226/Switch.jpg

its connected to the vac hose that goes to the Vacuum Actuator.
thanks!

I do believe that is for the front diff actuator thats directly under the battery tray.

Can't tell for sure from the image, but it looks like the vent hose for the front differential. Maybe take another shot from another angle.

I was going to try and explain it, but heres all the info you need:

http://199.79.180.162/prepos/files/Artemis/Public/Recalls/1999/V/RCRIT-99V193-6648.pdf

Thanks! Now i know why it was attached to the vac hose that goes to the Actuator. It serves as a switch so your ABS will know if your in 4wd or not.

^^^^^^^Thanks for the PDF, Ive been looking for that for a while now.