The cruise control system in a 2000 Jeep Grand Cherokee typically relies on the vacuum system to function properly. When an animal chews through the vacuum lines, this can disrupt the system and cause the cruise control to stop working. Here are some steps and information that might help you diagnose and repair the issue:

### Key Components of the Vacuum System Related to Cruise Control:
1. **Vacuum Reservoir**: Stores vacuum to provide consistent vacuum pressure for the cruise control system.
2. **Vacuum Lines**: Tubes that carry vacuum from the engine or vacuum pump to the cruise control actuator.
3. **Cruise Control Actuator**: Uses vacuum pressure to control the throttle.
4. **Check Valves**: Ensure vacuum only flows in one direction.
5. **Throttle Body**: The part of the engine that regulates the amount of air flowing into the engine in response to driver inputs on the accelerator.

### Steps to Diagnose and Repair:
1. **Locate the Vacuum Reservoir**: This is usually a plastic ball or container mounted somewhere in the engine bay or behind the bumper.
2. **Inspect Vacuum Lines**: Trace all vacuum lines from the reservoir to the cruise control actuator and inspect them for damage.
3. **Replace Damaged Lines**: If you find any chewed or damaged lines, replace them with new vacuum hose of the same diameter and length. Ensure a tight fit to prevent any leaks.
4. **Check the Actuator and Connections**: Inspect the connection points at the actuator and the throttle body. Ensure there are no cracks or breaks.
5. **Test the Check Valves**: Remove the check valves and blow through them. They should allow air to pass in one direction only. If air passes in both directions or not at all, replace the check valves.

### General Vacuum Line Routing Diagram (For illustrative purposes, locations may vary):
1. **Vacuum Source**: Connection point generally at the intake manifold or a dedicated vacuum pump.
2. **Check Valve**: Located between the intake manifold and vacuum reservoir to prevent backflow.
3. **Vacuum Reservoir**: Stores vacuum.
4. **Cruise Control Vacuum Supply Line**: Runs from the vacuum reservoir to the cruise control actuator.
5. **Cruise Control Actuator**: Mounted on or near the throttle body, connected via a linkage or cable.
6. **Throttle Body**: Connection point where the cruise control actuator adjusts the throttle position.

## Example Vacuum Diagram

```
(Intake Manifold or Vacuum Pump)
|
|
(Check Valve)
|
|
(Vacuum Reservoir)
|
|
(Cruise Control Supply Line)------------>(T-Connector)----->(Other Vacuum System Components)
|
(Throttle Body)
```

### Tips and Precautions:
- **Safety First**: Disconnect the battery before working on the vehicle to avoid any accidental starts or electrical issues.
- **Vacuum Hose Size**: Make sure to use the correct diameter hose. Using the wrong size can result in improper vacuum pressure and system failure.
- **OEM Parts**: When possible, use original equipment manufacturer (OEM) parts to ensure compatibility and durability.
- **Testing**: After replacing the lines, test the cruise control system by taking the vehicle for a test drive on a safe and controlled environment.

### Additional Resources:
- **Service Manuals**: Refer to the Jeep Grand Cherokee service manual for detailed diagrams and part numbers.
- **Online Forums**: Websites and forums dedicated to Jeep owners often have detailed guides and community support.

By following these steps and using the diagram as a guide, you should be able to identify and repair the vacuum leak affecting your cruise control system.