The 1997-2001 Jeep Cherokee XJ has a rear cargo light that you push to turn the light on or off. If the rear cargo light switch is off then when you open any of the four doors then the cargo light, as well as the dome light and footwell lights, will come on. If the doors are all closed and you open the tailgate then none of the lights come on. If the rear cargo light is pushed on then if you open the tailgate the cargo light and the dome light will come on. If the switch in the cargo light has melted then the switch will be permanently off. The switch is removable from the cargo light. The switch was made by ETN (Eaton) and appears to be no longer available. Most of the time the switch will overheat and plastic from the switch will melt and flow into the switch making it unrepairable. The heat damage does not appear to cause too much damage to the cargo light housing or pins. Honda uses an almost identical light switch, but it is a bit too tall. The Cherokee has a pedestal on the clear light housing that can be cut off. This will allow you to use the longer honda switch to replace to original ETN made in Mexico switch. Another alternative is you replace the entire cargo light assemble. Instead of removing the pedestal on the light switch, you might be able to cut the height of the switch down. I didn't try this route but I probably should have. The part number for the Honda switch is 34404-SDA-A21, 34404-SDA-A22D3. The part runs about $7 for 2 on Ebay. Used cargo light assembles run about $20 on Ebay.

Original 1999 Jeep Cherokee Classic rear cargo light. It has melted and the switch is in the off position.

With the Honda replacement switch. Cover installed backward so that you can see the pedestal has been cut off.

Remnants of the cut off pedalstal.

Cover with the pedestal cut off.

Original switch on the left. Honda on the right.

Original on the right. Honda switch on the left.
a used replacement is about $20. The Honda switches run about $7 for 2. This repair was made on a 1999 Jeep Cherokee Classic.