A TJ that cranks intermittently, dies at random, or won't power up when you turn the key often has a failing ignition switch, not a deeper problem. It is one of the platform's known faults, and the electrical switch behind the lock cylinder is a cheap, hour-long fix — far cheaper than the parts cannon people aim at a no-start.
The TJ ignition assembly has two parts: the mechanical lock cylinder (the key tumbler) and the electrical switch behind it that actually sends power to the run and start circuits. The electrical switch wears and develops intermittent contact, which shows up as a Jeep that sometimes won't crank, cuts out over bumps, or loses accessories momentarily.
Confirm it's the switch, not the battery or grounds. With a multimeter, check for steady power at the switch's run and start outputs while wiggling the key and turning through positions. Intermittent or dropping voltage at the switch outputs, especially when you jostle the key, points at the switch. Clean, tight battery terminals and grounds rule out the cheaper culprits first.
Disconnect the battery. Drop the steering-column shroud (a few Torx screws), and the electrical switch unclips from the column behind the lock cylinder — you can usually replace it without pulling the cylinder or the airbag-clockspring. If the key feels sloppy or sticks, replace the lock cylinder at the same time.
Because the symptom is intermittent, owners chase fuel pumps, crank sensors, and relays first. Test the ignition switch early — it's a known TJ weak point, the part is inexpensive, and catching it saves a long, expensive diagnostic detour. A quick tell in the field: if cycling the key a few times or jiggling it brings the dead Jeep back to life, suspect the switch first — a fuel pump or crank sensor does not care how you hold the key, but a worn ignition switch does.
| Part | Vendor | Est. price |
|---|---|---|
| Ignition switch (electrical portion) | Mopar/Standard | ~$60 |
| Ignition lock cylinder (if worn) | Mopar | ~$50 |
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.