I have a 2001 dodge ram sport 4x4. Everything that's vacuum operated does not work, the 4 wheel drive will not engage the cruise control and the vents are not working. The only thing that still works is the power brakes. Any help would be greatly appreciated

 

You need to visually inspect the vacuum lines. The vents vacuum line goes in right by the AC lines. The 4wd see if you are getting vacuum on one of the lines. Cruise line goes in under the battery tray check to see if it's broke.

 

+1 on a visual inspection.
The line that goes through the firewall with the A/C lines is a classic place for chafing a hole, if not completely severing it.

 

Thanks for the info, I'll double check all the lines.

 

There may be check valves installed in some of the lines, make sure they are installed in the correct direction.