Replace the 1984-1996 sealed-beam 7x6 headlamps with H4 conversion housings (Truck-Lite 27270C or Hella 003177801) for vastly better light using replaceable bulbs.
Pre-1997 XJs use the dim DOT 6054 sealed-beam rectangular lamps (7x6 inches). They produce roughly 20% of what a modern projector does. The standard fix: drop in 7x6 H4 housings — Hella E-code with 60/55W H4 bulbs has been the enthusiast pick for 25 years; Truck-Lite LED (27270C) is the modern equivalent for $200/pair and is DOT-legal.
No wiring mods strictly required — the factory connector adapts via included H4 pigtails. HOWEVER: the factory headlight wiring is undersized 18 AWG and routes B+ through the dash switch. If you upgrade to higher-wattage bulbs (80/100W H4) you MUST install a relay harness (Painless 30815 or similar) that feeds battery+ directly to relays triggered by the dash switch — otherwise you cook the switch and get dim output.
1997-2001 XJs already have composite housings with replaceable 9004/9007 bulbs — a different upgrade path applies (see LED bulb retrofit). For SOA (square optic axis) bulbs in H4 housings, aim properly — bad aim from a great bulb is worse than mediocre aim from a stock bulb. Use a wall 25 feet away at the proper height.
| Part | Vendor | Est. price |
|---|---|---|
| Hella H4 E-code 7x6 conversion (pair) | Hella | ~$90 |
| Truck-Lite 27270C LED 7x6 (pair) | Truck-Lite | ~$240 |
| Painless headlight relay harness | Painless Performance | ~$80 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.