If you own a Jeep Wrangler and experiencing intermittent starting or no crank at all then this article is for you. We will identify what the possible cause is of power loss, no crank, and why your Jeep won’t turn over. It’s not always simply a bad battery. Possible issues could be a bad starter or solenoid. Are you getting fuel supplied? Perhaps a loose earth connection or electrical corrosion on the battery terminals? We will discuss all these and more in this article, and explain in detail how to troubleshoot each.
Why won’t your Jeep Wrangler start? Your Jeep Wrangler won’t start if you have any of the below faults:
- Dead or Low Voltage battery
- A bad Starter
- Loose Earth Cable
- Faulty Ignition Switch
- Battery Terminal Corrosion
- A faulty Solenoid
- Bad Starter Relay
- Faulty Park Neutral Safety Switch
So we’ve identified a few potential culprits that could cause your trusty Wrangler not to start. But how do we isolate which component it actually is? The last thing you want to do is run out and spend a load of money on a replacement battery, only to find out it was just a loose earth strap connection in the end. Not cool!
So, let us see what tests we can carry out to determine which component is faulty and what needs replacement. Let’s get into it.
My Jeep Wrangler Won’t Turn Over
The first thing we want to determine is the age of your battery. Many people seem to forget that car batteries only last about 2-3 years nowadays, after which you can expect it to die at any time. Usually, there is some sort of inscription or date stamp on the battery which indicates its age or purchase date. If your batter is well over 3 years you’re probably due for a replacement soon anyway. So checking battery age is critical.
Next, you want to determine if the battery is fully charged and if it can still handle the required cranking load. How do we do that?
Well, the most effective is to hook up a voltmeter and take a reading under the load setting. The first starting point when diagnosing a dead battery is to verify your battery has the correct voltage. Incorrect or low power to the starter will not start your Jeep.
Batteries use CCA (Cold Cranking Amps) to measure starting power. Be aware that your battery could have power, however, when under load, the cranking amps are not powerful enough to get the starter to crank the engine. A good fully charged battery should read over 12.6 volts. If the battery reads 12.45 volts or less, it is low. If your battery is reading less than a 75 percent charge it needs to be recharged or replaced if it has expired. Battery voltage readings drop with ambient temperatures. A rough guide is 0.01 volts for every 10 degrees F. (-12.2 Celsius)
So if you’ve determined that your battery is healthy and fully charged, how do we go about testing the starter? Remember, the starter only has one function, and that is to turn/crank the engine. That’s it! If the engine is turning over but not starting your problem lays elsewhere. Starters usually last many years and can endure thousands of starts, however, if your Jeep has been regularly exposed to rivers or beach water, mud, and other moist or dusty conditions, it could drastically reduce the lifespan of your electrical components.
Typical symptoms of a bad starter is, it has no cranking functionality and just a clicking sound. The clicking sound you hear is the solenoid trying to engage the starter. The starter gears and spindle could be jammed up inside or worse case, the wire cores could be burned out completely. The starter will draw heavy current to try and start/turn the engine, however, if the battery voltage is low it could burn out the brushes or even the entire wiring inside, completely destroying it.
Typical symptoms of a bad starter are:
- Lights on but no crank
- Clicking sounds
Loose Earth Cable
Jeeps have been known for somewhat inadequate grounding, so don’t overlook this part. Make sure you have sufficient ground contact and the earth strap is still in good condition. You might even have to install a second earth ground cable if need be. In many cases, the electrical faults on Jeeps aren’t usually electrical as they are more ground related. Electrical components don’t only need the correct power but also a solid ground to function correctly.
Have a look at this quick video where Matt shows us how to repair a broken or corroded ground wire on a 2007 Jeep Wrangler.
A good way to test your ground is by means of your volt meter. You do this by placing the positive point on the positive battery post, and the negative lead on a clean metal surface on the starter body, or the solenoid mounted on it. Make sure the metal surface is clean and free of any grease or oil on the starter will suffice. Ensure the voltage reading you get at rest is the same as the battery reading at rest.
Many Wrangler owners have reported faulty ignition switches. The key is stuck in the ignition start position, unbeknown to the driver. This results in the starter constantly engaging and eventually burning out. If you are unaware of the strange sound it makes, it can go undetected and the starter will eventually fail. Inspect the ignition switch actuator pin. It’s a bad design and a bit of an inferior design. Jeep has had many issues with these parts as far as recalls go.
The below video demonstrates how to install an ignition switch on a Jeep Wrangler.
|Component||ELECTRICAL SYSTEM: IGNITION: SWITCH|
|Summary||ON CERTAIN SPORT UTILITY VEHICLES, WATER AND IMPURITIES CAN ENTER INTO THE IGNITION SWITCH, CAUSING A SHORT CIRCUIT|
|Consequence||THIS COULD RESULT IN A VEHICLE FIRE|
|What Owners Should Do||DEALERS WILL REPLACE THE IGNITION SWITCH WITH A REDESIGNED SWITCH. OWNER NOTIFICATION BEGAN APRIL 8, 2002. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT DAIMLERCHRYSLER AT 1-800-853-1403.|
My Jeep Won’t Start but It Turns Over
To diagnose, you first need to determine if the problem is electrical or fuel related. If you have determined that fuel is being supplied all the way to the injectors then your next option is to inspect for electrical spark. Make sure you are getting a good strong spark to all your plugs.
If your starter spins but it does not start/crank the engine then you have a starter problem. The spindle or drive inside the starter is possibly damaged. If the starter is repairable, you can have the drive spindle replaced, otherwise you’ll need to replace the starter. It is also possible (but unlikely under normal circumstances) that your driveshaft is snapped, or the planetary track in the starter is worn, in which case a new starter is in order. Don’t forget to inspect for damaged teeth on the flywheel.
Jeep Won’t Start but Has Power 2018+
Many reports of 2018 jeep Wranglers suddenly not starting at random intervals. Owners would stop to fill up at a gas station only to be stranded with a non-starting Jeep. All of the lights turn on and the
radio works. But no engine sound. No prior warnings signs either. Many reports indicate the battery and starters are all new or have been recently replaced, ruling those options out.
The vehicle would randomly just start again, sometimes after about an hour. What could possibly be the cause?
In this instance, it could be the transmission temperature switch. This means your transmission is running over the temperature limit. Hence, after sitting for about an hour it cools down and allows you to restart again as if nothing was wrong.
In this instance, you want to make sure your transmission fluid is full, so check the fluid levels first and top-up if necessary. If the fluids are full, check your cooling temperature sensor.
If all else fails, another thing you can do is, try starting your Jeep from the (N) neutral position. Turn the key enough to move from park to neutral. Hold your foot on the brake while turning the key to start the ignition.
Jeep Wrangler JK Won’t Start One Click
If your Jeep won’t start and you simply hear one click, then you could have a faulty starter motor. Again, using a voltmeter with a load function, make sure all your voltages are all correct. The solenoid could have enough power to engage and feed current to the starter, but a loss of current in the ground cable or faulty battery could be causing the starter to not crank properly.
Always diagnose your starting with the easy components first like your earth cable, corrosion around the battery terminals, and unsecured battery connections. Next move to transmission fluid levels and sensors. If all of those are fine inspect the ignition switch and battery health and then lastly move to the more expensive components like the starter and battery replacement if necessary.
Know your clicks:
No click: dead battery
Rapid clicks: Earth Ground Faulty
One Click: Faulty Starter