Not quite as simple of a fix.

Tonight I was working on my brother's Grand Cherokee and was hoping for similar success. His hoses hadn't become disconnected, but were cracked and needed replacement. I replaced the three hoses in the intake manifold and another hose by the ABS controller. All were easily accessible on the drivers side.

Unfortunately, this didn't fix the issue. So, I connected a vacuum pump the vacuum line with the check valve. I believe it was the middle of the three hoses on the intake manifold, the only one with a check valve. It would not hold vacuum. It is the hose that supplies the vacuum for the AC and Cruise control.

I followed the black plastic line that connects to the vacuum hose to the passenger side and it disappeared under the battery tray. I removed the battery and battery tray. (Takes about 1/2 hour). I found another extremely cracked vacuum line going from the plastic line to the cruise actuator. Once it was replaced, I tested with my vacuum pump and it held vacuum fine. I reinstalled the battery tray and battery.

Now all is working fine.