We've all seen Jeeps with wiring like this. Some of us have even started out with wiring in our Jeep worse than this. However, since each rat's nest of wiring is unique to each Jeep, a story about it would be boring and not applicable to your rig. Instead, we'll assume you've already evicted your rats and show you our top 10 basic electrical upgrades.
These are relatively inexpensive tricks we've learned over the years, which will keep you much happier with your Jeep's electrical system, modifications, and devices as time goes on.
We aren't big fans of sealed...
We aren't big fans of sealed beam lights. Their output is less than adequate for anything other than on-road, perfect-weather usage. We tend to replace our headlights with H4-style housings. Not only does that open up a whole new range of lighting colors and wattages, but the pattern is also typically more useful than a sealed beam light. If you kick the wattage up beyond 55 watts on low beam and 65 watts on high beam, add a relay for each headlight too or risk frying your headlight switch.
One of the things we do on...
One of the things we do on every Jeep when adding lights, stereos, or whatever is to add a circuit breaker right next to the battery. Run a heavy gauge wire to it (four gauge or higher) and then run your accessories off of the breaker. The breaker is better than a big fuse and cheaper in the long run simply due to the fact that you won't have to replace it whenever you trip it (just reset the breaker when that happens). And if you are working on something downstream of the breaker, just hit the button, and you won't run the risk of getting zapped.
Unless a team of race mechanics...
Unless a team of race mechanics maintains your Jeep, there will come a time when you will have to inspect or wrench on something in the middle of the night. We like adding underhood lights that have retractable cords. Some XJs and MJs came with auto-retracting units, but the best ones can be found under the hood of Chevy trucks. Look for the light with the manual crank handle. The automatic ones will always die on you, much like that old vacuum cleaner cord retractor.