Jeep Wrangler YJ & TJ Relay Guide (1987-2000): Solving No-Start Issues
A tiny, inexpensive relay is often the only thing stopping your 1987-2000 Jeep Wrangler from starting.
- Diagnose the problem by how it fails: 'crank but no start' often means a fuel/ASD relay, while 'no crank' points to the starter relay.
- On 1997-2000 TJ models, you can swap the suspect relay with the horn relay to confirm failure.
- Relay replacement is one of the easiest DIY jobs, requiring no tools and taking only minutes.
- For this simple part, an aftermarket relay is a reliable and cost-effective solution.
Is Your Wrangler Cranking But Not Starting? Or Not Cranking at All?
When your Jeep Wrangler won't start, the issue is often a failed relay, not a more expensive part like the fuel pump or starter. Relays are simple components that wear out over time from heat and constant use. How your Jeep fails to start is the biggest clue. There are two main scenarios:
- Engine Cranks, But Won't Start: This classic symptom often points to a bad fuel pump relay or Automatic Shutdown (ASD) relay. 🎬 Learn how the ASD relay operates and how to test it. The starter is turning the engine over, but the engine isn't getting fuel or spark to run.
- Engine Won't Crank (or just one click): If you turn the key and hear a single click or nothing at all, the starter relay is the most likely culprit. The relay isn't sending the high-power signal to the starter motor.
Finding and Testing the Relay
The location of your relays depends on your Wrangler's generation.
- 1997-2000 (TJ): Most critical relays are in the black box in the engine compartment called the Power Distribution Center (PDC), located near the battery. The cover of the PDC has a diagram showing which relay does what (e.g., FUEL PUMP, HORN, STARTER).
- 1987-1995 (YJ): Relays are often found in a fuse/relay block in the engine bay, but some, like the starter relay, may be mounted individually on the firewall on the passenger side. 🎬 See this walkthrough for locating YJ ignition relays.
Pro Tip: The Relay Swap Test (TJ Models)
On TJ Wranglers, many relays in the PDC are the same part number. If you suspect a bad fuel pump relay, you can swap it with the horn relay. If the horn now doesn't work but your Jeep starts, you've confirmed the relay was the problem. This is a free and effective way to diagnose the issue on the trail.
🎬 Watch: A quick fix for TJ hard start relay issues.Choosing a New Aftermarket Relay
For a simple, standardized part like a relay, there is little practical difference between an OEM Mopar part and a quality aftermarket one for daily driving and moderate off-road use. The main difference is price. An aftermarket relay from a brand like Replacement offers the same function and fit at a lower cost. Given the ease of replacement and low price, many owners choose to keep a spare in their glove box.
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Relay | $17.03 |
| New OEM (Mopar) Relay | $25 - $35 |
| Shop Labor | $47 - $72 |
| Total Shop Replacement (Aftermarket) | $64 - $89 |
Frequently Asked Questions (FAQ)
Where is the fuel pump relay on a 1987-2000 Wrangler?
On 1997-2000 TJ models, the fuel pump relay is in the Power Distribution Center (PDC) in the engine bay, near the battery. On earlier YJ models, it is typically in a fuse/relay block in the engine bay.
Can I drive with a bad relay?
No. A failed critical relay (fuel, starter, ASD) will prevent the vehicle from starting or cause it to stall unexpectedly. It is not safe or possible to drive until the faulty relay is replaced.
Are the fuel pump and starter relays the same?
On many 1997-2000 TJ models, yes. They often use the same multi-purpose relay part number and can be interchanged for testing. The function is determined by which circuit it's plugged into in the fuse box. For YJ models, you should verify the part numbers as they can differ.
Why are my relays clicking rapidly when I try to start my YJ?
On older YJ Wranglers, rapidly clicking relays can be a symptom of failing capacitors inside the Powertrain Control Module (PCM). This is a known issue for YJs of this era. While the relays themselves might be good, the faulty PCM signal causes them to chatter. Another common cause for clicking relays on any vehicle is a weak or dead battery.
Helpful Videos
Technical Specifications
OEM Part Numbers: 4671168 56006846 4606418AA 4606409AA
This is a multi-purpose ISO relay commonly used for the fuel pump, starter, ASD, A/C, and horn circuits on Jeep TJ models.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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