Jeep Wrangler Won’t Start: What Could Be The Problem?

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At first glance, the Jeep Wrangler might seem like an ordinary car. But dig a little deeper and you’ll discover it’s a vehicle built to last—not just for one generation.

With a manufacturer that has been around since the WW2 generation, Jeep has created a unique beast, an off-roader that can handle any terrain.

Even with so much history, the Jeep Wrangler is prone to issues found in other vehicles.

One of them is the vehicle not starting at all, which has led to a surprising reaction, from the owners, of “Why Won’t My Jeep Wrangler Start?”. This can be due to several reasons.

Let’s take a look at them:

  1. Dead Battery
  2. Disconnected Battery Cables
  3. Failed Ignition Switch
  4. Faulty Immobilizer Security System
  5. Faulty Alternator
  6. Starter Relay Issues

Now that I have listed the most common reasons that may prevent your Jeep Wrangler from starting let’s take a look at them in detail. I suggest you don’t skip over anything in this article as the information is vital.

So, without any further ado, let’s get straight into it.

What Would Cause A Jeep Wrangler To Not Start?

Why won’t your Jeep Wrangler start? You may be stumped and confused. Whether you are on the side of the road or in your driveway, all dressed up for office in the morning. This is indeed a frustrating situation.

Let’s see why this happened.

1: Dead Battery

If your Jeep Wrangler won’t start, the first thing to check is the battery. It’s easy to look at a battery and assume it’s dead, but there are a few things you can do before you give up on it and buy a new one.

Now, there can be many reasons which can result in the battery dying prematurely. It simply could be that there is corrosion on top of the terminals, preventing current from passing through.

Another reason for the battery dying could be the temperature. The weather may not suit the battery if it is too hot or cold.

What Should You Do About It?

  • Check that all the connections are tight and free from corrosion. Corrosion can cause a build-up on the terminals and prevent them from making good contact with the posts on your vehicle’s battery.
  • You can use a wire brush to clean up the corrosion.
  • You can check whether or not it’s the battery by jumping it with another vehicle or using jumper cables and another set of batteries.
  • If the jumper cables don’t work, it could very well be the dead battery. (I highly recommend you read this 5 Best Batteries For Jeep Wrangler article).

2: Disconnected Battery Cables

When the battery cables are disconnected, the engine will not start. This can happen if you accidentally disconnect the cables while working on your Jeep Wrangler.

The most common reason is changing the oil or adjusting your battery posts. People do this to prevent themselves from getting electrocuted.

If you have an older Jeep Wrangler, you’ll want to ensure that the cables aren’t frayed or cracked, which can cause electrical flow problems. Such cables are easy to spot, and they can cause the engine to not receive enough power to turn over.

What Should You Do About It?

  • If your battery cables are disconnected, all you have to do is reconnect them! You’ll need a new set of battery cables if yours have been damaged by corrosion or if they’re too short for where they need to go (usually under the hood).
  • If not, just make sure they’re connected properly and give it another go.
  • If the Jeep still does not start, then all you can do is replace the wires. They may have become frayed or damaged throughout their lifespan. New battery wires do not cost a lot.

3: Failed Ignition Switch

The ignition switch can fail due to age or wear and tear. If this happens, you may find yourself unable to start your car. This is not a problem unique to the Jeep Wrangler; many other cars have experienced similar problems with this particular part.

If your ignition switch does fail, it should be replaced as soon as possible so that you don’t experience any further issues with starting your car.

There is one possible reason for the switch failing. The contact points on the switch itself may have worn down over time. This can cause them not to make good contact with each other when they’re supposed to be closed (which means they won’t turn on).

What Should You Do About It?

  • If it’s determined that your ignition switch is failing and needs replacing, this is what you need to do:
  • You’ll need to remove the cover from your steering wheel. This will give you access to the back of the ignition switch, where a small screwdriver can be used to remove it from its housing.
  • Then, pull out the old ignition switch and put in a new one. Make sure all wires are properly connected before returning everything together!
  • Repairing an ignition switch is not recommended, and a replacement is the only viable option.

4: Faulty Immobilizer Security System

The Immobilizer Security System is a device that prevents your car from starting if there’s something wrong with it. If the Immobilizer Security System doesn’t work, you won’t be able to start your Jeep Wrangler.

The problem can occur when the vehicle’s computer has lost its memory, or the battery has discharged. Other causes include an electrical short or a bad connection in the wiring harness.

What Should You Do About It?

  • If you’re having trouble with your Jeep Wrangler’s immobilizer security system, there are some things that you can do at home to try and diagnose the problem yourself:
  • Check for loose connections in the ignition area of your vehicle or around the steering column.
  • Ensure all wiring is connected securely with no exposed wires or connectors visible from beneath the dashboard or steering column covers.
  • If so, then tighten up any loose connections or replace any damaged wires before taking further steps towards fixing whatever problem may be causing these issues to avoid more damage being done while trying.
  • If this does not work, the immobilizer system may be at fault. It may need replacing, which can only be done by a professional.

5: Faulty Alternator

If your Jeep Wrangler doesn’t start, it may be because the alternator is not working properly. The Jeep Wrangler uses a belt-driven alternator that charges the battery by converting mechanical energy into electrical energy.

The alternator is connected to the engine’s crankshaft and spins in sync. A faulty alternator will not let the battery charge, and it may get depleted, which will result in the engine not turning over.

What Should You Do About It?

There are several ways to test whether or not your alternator is faulty:

  • When the SUV is running, try to disconnect the battery’s negative terminal. If it shuts down, then the alternator is indeed faulty. It is not generating enough electricity to keep the engine running.
  • You can also check the voltage of the battery. The voltage should be around 12V. If it is lesser than that, then that means it is not being charged, which is the responsibility of the alternator.

An alternator can only be replaced, and you need to get that done by Jeep itself. It can be costly, but it is important to ensure your SUV can keep running.

6: Starter Relay Issues

Another common reason is a starter relay issue if your Jeep Wrangler won’t start. The starter relay is a switch that tells your Jeep’s electrical system to send power from the battery to the starter motor.

This helps prevent overload when you try to start your Jeep and protect both your battery and starter motor from damage. If this relay is faulty, it means you need to replace it.

What Should You Do About It?

  • Just like with the ignition switch, the best thing to do is to replace the relay entirely.
  • You really don’t want to be driving around with a repaired relay, which has a decent chance of failing once again. You can check one more thing before getting it to a mechanic.
  • Check the fuses. There may very well be an issue with the relay’s fuse. You can replace it and check if your Jeep Wrangler starts.
  • If this does not work, then replacing the relay is the only option. Fortunately, new ones are pretty cheap, and you can get away with a total replacement cost of less than $100.
  • Yes, this includes the cost of buying the relay! Your Jeep Wrangler can be up and running after this small expense.

Frequently Asked Questions

Q1. Why Won’t My Jeep Wrangler Start With New Battery?

If you’re having trouble starting your Jeep Wrangler, it’s probably because your new battery needs to be charged.

This can happen if the battery wasn’t fully charged when you bought it or if it was sitting on a shelf for too long.

Don’t worry. You can buy a charger and get the battery up and running in a few hours.

Q2. Why Won’t My Jeep Wrangler Start Even With A Jump?

When a car’s battery dies, it can sometimes be brought back to life with a jump. If that does not work, then you should know that the battery has reached the end of its lifespan.

To really confirm if the battery is not the source of the issue, try turning the headlights on. If they don’t, then your battery is indeed dead.

Q3. Why Won’t My Jeep Wrangler Start But Lights Work?

If your Jeep Wrangler won’t start, but the lights are working, it’s probably because the battery has died. This is a common issue with Jeeps, especially if they are starting to age.

The best thing you can do is jump-start your car using another vehicle. If that doesn’t work, you may need to replace your battery.

Q4. Why Won’t My Jeep Wrangler Start But Cranks?

If your Jeep Wrangler won’t start but cranks, you might have a bad starter. The starter is what kicks the engine into gear when you turn the key, so if it’s not working properly, it can be hard to get it started. You will need to get your SUV checked by a professional to properly diagnose the issue.

Q5. Why Won’t My Jeep Wrangler Start Just Clicks?

When you try to start your Jeep, the starter is supposed to engage and turn over the engine. If it’s not doing that, it’s likely because of a charging issue—your battery’s charge isn’t enough to power the starter circuit.

The SUV could be sitting for too long in cold weather. If the battery is drained, you can charge it up or jump-start it.

Q6. Why Won’t My Jeep Wrangler Start In The Cold Weather?

The most probable reason could be that the battery has not been designed for use in such low temperatures.

What you can do is buy a new battery that has higher cranking amperage, so you can finally get rid of the issue of your Wrangler not starting in cold weather.

Q7. Why Won’t My Jeep Wrangler Start After I Get Gas?

The only thing to check is the fuel filter, which is located near the gas tank under the hood of your Jeep Wrangler.

If you see any fuel contamination in it, replace it with a new one. A clogged filter will not let fuel pass through and enter the engine, which will result in the engine not starting.

Q8. Why Won’t My Jeep Wrangler Start But Radio Works?

It could be that the battery has a low charge. The charge level may be enough that it cannot start the engine, but it may be high enough to turn on the radio.

This is a common occurrence. The battery of the Jeep Wrangler could either refuse to hold a charge, or it may just be depleted.

Related: What Are The Worst Years For The Jeep Wrangler?

Conclusion

If you have a Jeep Wrangler and it won’t start, you’re not alone. I’ve been in your shoes, and I know it’s frustrating. I hope I’ve helped shed some light on why your Jeep might not be starting and what to do about it.

To answer your question of “Why won’t my Jeep Wrangler start?”, there can be many reasons for it. This article has discussed all of them in detail, so you can rest assured that the most probable reason will be found on this page.

I hope you got the information you were looking for, and I hope that you can get your Wrangler fixed and be on your merry way.