Blown Start Fuses

I have a 97' XJ Sport with the 4.0 I6. It has 221,000 miles. Every now and again it goes through a spell where it will blow 2 or 3 starter fuses (30 amp) a month. The fuses that are blowing are located in the black box under the hood. Not sure where to start looking for culprit. Andybody seen this before?

Dirty or loose connections, or corroded wires. Have the starter tested.

Begin with basic trouble shooting of the start and charge systems. Remove, clean, and firmly reconnect all the wires and cables to the battery, starter, and alternator. Look for corroded or damaged cables or connectors and replace as needed. Do the same for the grounding wires from the starter to engine block, and from the battery and engine to the Jeep's frame/body. You must remove, scrape, and clean until shiny, the cable/wire ends, and whatever they bolt to. Jeeps do not tolerate low voltage, bad connections, or poor grounds.

I'd follow the brown wire up from the starter solenoid where it goes into the PDC (I think there is a single connector hear the front for the starter solenoid) and press the wire between my index finger and thumb. Thirty amps is a lot of current and if the draw is high the wire often heats up. Disconnect the single connector and look to see if it is dark or obviously heat damaged.
Also a pink and black wire coming form that same fuse that goes to another junction block, Try to find that wire where it exits the PDC and check it for heat. Remove the fuse and look closely at the connectors for heat damage.
Do an ohm test on the solenoid wire with it connected to the solenoid. Any less the 1.0-1.2 ohms and it is likely you had a partial meltdown in the solenoid coil.

Check the solenoid wire (brown) where it runs down the side of the engine block, my 96 had that wire partially rub through, though I'm not exactly sure if the 97 runs the same cable routing or not.

Thirty amps is enough to cook and melt a wire and if your solenoid wires are the same as my 96 are, kind of anemic (under size) anyway.