I recently picked up a new-to-me 88 4.0 Cherokee. I've been trying to get the cruise control working. I found that the connector at the brake light switch was disconnected, so I plugged that back in. I also checked the fuse while I was down there and it is fine. The next thing I checked was vacuum, and I have none at the servo. Is there supposed to be vacuum there all the time, or is it controlled by a valve somewhere externally? I read in the service manual that there is a valve to break the vacuum to disengage cruise control, but I thought that was internal to the servo. My mutlifunction switch is a little screwy so it may be an electrical issue with it, but I want to check the easier things first. Where does that vac line run to?