1. Verify the Fuse is Actually Blowing:
* Don't just replace it: Before replacing the fuse, carefully inspect the blown fuse. Make sure it's actually blown (the internal wire is broken). If it's not blown, you have a different problem entirely.
* Use a replacement of the correct amperage: Only use a 15-amp fuse. Using a higher amperage fuse is a fire hazard.
2. Isolate the Circuit:
Your owner's manual should have a fuse box diagram showing which circuit the fuse protects. It's *likely* the reverse lights, but it *could* be something else sharing that fuse.
3. Check the Reverse Lights:
* Visual Inspection: With the jeep OFF, inspect the reverse light bulbs and sockets for any signs of damage, corrosion, or shorts.
* Wiring Inspection (Difficult): Carefully examine the wiring harness leading to the reverse lights for any fraying, damage, or bare wires that might be shorting against the chassis. This often requires removing some trim pieces.
* Test the Bulbs (Easy): If you have a multimeter, test the resistance of each reverse light bulb to ensure they aren't shorted. If one is shorted, it will draw excessive current. A shorted bulb will read near zero ohms (or very low resistance). A good bulb will have significant resistance (tens of ohms). If you don't have a multimeter, test the bulbs by swapping them with known good bulbs from other working lights in the jeep.
4. Check the Reverse Light Switch:
The reverse light switch is a crucial component. It's usually located on the transmission. When you shift into reverse, this switch closes a circuit, completing the pathway for the reverse lights.
* Inspect for Damage: Look for any signs of damage, corrosion, or wear on the switch itself.
* Test the Switch (Advanced): This requires a multimeter and some electrical knowledge. You'll need to access the switch and test its continuity when the transmission is in reverse and neutral. This is beyond a basic DIY repair and may require consultation of a wiring diagram.
5. Consider Other Possibilities (Less Likely):
While less probable, given the specific circumstances, consider:
* Trailer Wiring: If you've recently used a trailer, a short in the trailer wiring harness could be drawing excessive current and blowing the fuse. Check the trailer wiring connector.
* Other Accessories: There might be an accessory (rare) on that circuit that is malfunctioning. The fuse box diagram will help identify potential culprits.
Important Safety Notes:
* Disconnect the Battery Negative Terminal: Before working with any electrical components, disconnect the negative terminal of your battery to prevent accidental shorts and shocks.
* Consult a Wiring Diagram: A wiring diagram specific to your 1999 Jeep Cherokee will be invaluable in this troubleshooting process. You can often find these online through Jeep forums or repair manuals.
If you're not comfortable working with car electrical systems, it's best to take your Jeep to a qualified mechanic. Ignoring a blown fuse can lead to further damage or even a fire.
