The Jeep Grand Cherokee has become a popular SUV for its combination of comfort, power, and technology. But when it comes to maintenance, some systems can be confusing especially the dual battery setup.
Many Jeep Grand Cherokee owners ask, “Where is the auxiliary battery in my vehicle?
” Locating and understanding this component is important for both troubleshooting and regular upkeep. Let’s break down exactly where to find the auxiliary battery, why it matters, and what you need to know as a Jeep owner.
What Is The Auxiliary Battery In A Jeep Grand Cherokee?
Modern Jeep Grand Cherokees (especially models from 2016 onward) often use a dual battery system. This means they have a main battery for the engine and a smaller auxiliary battery that supports the Start-Stop system, electronics, and backup functions. The auxiliary battery helps your SUV run smoothly, especially when the main battery is under heavy load.
Main Purposes Of The Auxiliary Battery
- Powers the Stop-Start system (engine shuts off at stops to save fuel)
- Supports accessory electronics (navigation, lights, infotainment)
- Maintains settings during battery changes
If the auxiliary battery fails, you might see warning messages, lose Stop-Start function, or experience electrical issues.
Where Exactly Is The Auxiliary Battery Located?
Finding the auxiliary battery in a Jeep Grand Cherokee isn’t always obvious it’s not visible when you open the hood. Jeep engineers placed it in a compact location to save space and protect the battery from heat.
Typical Location
For most 2016–2023 Jeep Grand Cherokee models, the auxiliary battery is located:
- Under the passenger seat or
- Inside the engine compartment, hidden beneath the main battery
The most common setup is that both the main and auxiliary batteries are stacked together in a special compartment under the hood, on the passenger side near the windshield.
Steps To Access The Auxiliary Battery
- Open the hood and locate the main battery cover (usually a black plastic box).
- Remove the cover using a screwdriver or by unclipping.
- You’ll see the main battery on top.
- Under the main battery, inside the same compartment, you’ll find the auxiliary battery.
Some models require you to remove a crossbar or bracket before you can take out the main battery and reach the auxiliary.
Location Differences By Model Year
Not all Grand Cherokees are the same. Here’s a quick comparison:
| Model Year | Main Battery Location | Auxiliary Battery Location |
|---|---|---|
| 2011–2015 | Engine Compartment | No auxiliary battery (typically) |
| 2016–2021 | Engine Compartment | Under main battery, passenger side |
| 2022–2023 | Engine Compartment | Under main battery, passenger side |
If your Jeep has Start-Stop technology, it almost certainly has an auxiliary battery.
Why Is The Auxiliary Battery Hard To Find?
Jeep designed the auxiliary battery to be out of sight for a reason:
- Protection from heat: Under the main battery, it’s shielded from engine temperatures.
- Space-saving: Stacking saves room in the engine bay.
- Less frequent service: Auxiliary batteries last about 3–5 years, so they don’t need regular checks.
However, this design means you often have to remove the main battery first before you can replace or inspect the auxiliary.
How To Replace The Auxiliary Battery
If your Jeep Grand Cherokee shows a “Stop/Start Unavailable” warning or struggles with electronics, the auxiliary battery could be the issue. Here’s a brief replacement guide:
- Turn off the vehicle and disconnect the negative terminal from the main battery.
- Remove the main battery cover.
- Unbolt and carefully lift out the main battery.
- Access the auxiliary battery below; disconnect its terminals.
- Replace with a new auxiliary battery of the same size and specification.
- Reinstall the main battery, connect terminals, and secure covers.
Tip: Always use a memory saver if you want to preserve radio presets and electronic settings.
Common Mistakes When Replacing
- Not disconnecting the main battery first (risk of short circuit)
- Installing the wrong battery type or size
- Forgetting to reconnect all terminals and sensors
If you’re unsure, professional installation is a good idea.
Signs Of Auxiliary Battery Problems
Not all battery problems are easy to spot. Here are some clear and less obvious symptoms:
- Stop-Start system stops working
- Dashboard shows “Stop/Start Unavailable” or battery warning
- Power windows, radio, or lights act strangely
- Clicking sound on startup
Less obvious: Sometimes, the main battery seems fine, but the auxiliary battery has failed. This can cause strange electrical issues even if the engine starts normally.
Cost Of Auxiliary Battery Replacement
Prices for Jeep Grand Cherokee auxiliary batteries vary. Here’s a general comparison:
| Battery Type | Average Cost (Parts Only) | Professional Installation (Approx.) |
|---|---|---|
| Main Battery | $150–$300 | $50–$100 |
| Auxiliary Battery | $60–$120 | $50–$100 |
Replacing both at the same time can sometimes save on labor costs.
Tips For Maintaining Your Jeep’s Battery System
- Check battery health every year, especially after three years of use.
- Keep battery terminals clean and free of corrosion.
- Avoid jump-starting unless necessary—this can damage the auxiliary system.
- Use only recommended battery types and sizes.
- If your vehicle has Start-Stop, don’t disable it unless necessary, as it’s designed to work with both batteries.
Is It Safe To Drive With A Bad Auxiliary Battery?
It’s possible to drive if the auxiliary battery fails, but you may lose features like Stop-Start and notice electrical glitches. Over time, a dead auxiliary battery can put extra strain on the main battery, leading to more expensive repairs. It’s best to address battery warnings quickly.
When To Replace Both Batteries
If your Grand Cherokee is more than four years old, or if you’ve already replaced one battery, consider replacing both. This can prevent future issues, especially if you rely on Start-Stop and advanced electronics.
Expert Insight: Many mechanics recommend replacing both batteries together, since they age at a similar rate and failure of one can strain the other.
For more technical details, you can check the official Jeep owner’s manual or visit the Jeep Maintenance Portal.
Frequently Asked Questions
Where Is The Auxiliary Battery In The 2018 Jeep Grand Cherokee?
In the 2018 model, the auxiliary battery is under the hood, stacked directly below the main battery, on the passenger side near the windshield.
Do All Jeep Grand Cherokees Have An Auxiliary Battery?
No, only models with Start-Stop technology (mostly 2016 and newer) have an auxiliary battery. Older models typically have only one main battery.
Can I Replace The Auxiliary Battery Myself?
Yes, but you’ll need to remove the main battery first. If you are not comfortable with car electronics, it’s safer to have a professional do it.
What Happens If My Auxiliary Battery Dies?
You may lose the Stop-Start function and see warning lights. Some electronic features may not work correctly, but the car will usually still start.
How Long Does The Auxiliary Battery Last?
On average, the auxiliary battery lasts 3 to 5 years, depending on driving habits and weather conditions. Regular checks can help catch problems early.
Finding and replacing the auxiliary battery in your Jeep Grand Cherokee is a key part of keeping your SUV running smoothly. With the right knowledge, you can avoid unexpected issues and enjoy all the modern features your Jeep offers.
