2020 Jeep Wrangler Battery Dead? Diagnose & Fix

How to Fix Battery Issue

Experiencing battery problems with your 2020 Jeep Wrangler can be frustrating. Many owners have reported issues ranging from dead batteries to auxiliary battery failures. As one owner, DatesForFun, shared: "what happened to me is the aux died and then drained the main battery and i was stuck with a dead 2020 wrangler." This guide will walk you through diagnosing and addressing common battery issues specific to your truck.

Symptoms

Several symptoms can indicate a battery problem in your 2020 Jeep Wrangler. Keep an eye out for these telltale signs.

One common symptom is a dead battery, preventing the vehicle from starting. This can manifest after the truck has been sitting overnight or for a few days. You might also notice the engine cranking slowly or not at all when you turn the key.

Another symptom reported by owners is a "service charging system" message appearing on the dashboard. This warning often accompanies a check engine light, indicating a potential issue with the battery or charging system. As Existing_Signal9173 shared, "While driving this morning the check engine light came on, so I turned around and came back home."

Issues with the auxiliary battery can also cause problems. The auxiliary battery is responsible for powering certain electrical components, and if it fails, it can drain the main battery, leaving you stranded. Some owners have experienced the auxiliary battery dying and subsequently draining the main battery, leading to a complete power loss.

Furthermore, unusual electrical behavior, such as lights remaining on even after the vehicle is turned off, can suggest a battery drain issue. "Should be able fix it easily with it out from the back side. If you need them off immediately to not drain your battery, there’s a fuse for the lights you can pull," suggested Crucial_memory when discussing troubleshooting stuck lights.

Most Likely Cause

Based on owner reports, the most likely cause of battery issues in your 2020 Jeep Wrangler is related to the auxiliary battery failing and draining the main battery. Many owners have pinpointed the auxiliary battery as the culprit behind their battery-related problems.

The auxiliary battery in your truck supports various electrical systems, including the start-stop system. When the auxiliary battery fails, it can create a parasitic draw on the main battery, gradually draining it and causing it to die prematurely. This issue is exacerbated by the fact that the auxiliary battery is often difficult to access and diagnose.

Another contributing factor is simply the age and condition of the batteries themselves. Over time, batteries naturally degrade and lose their ability to hold a charge, especially in extreme temperatures. A weak or old battery can quickly become a problem, particularly if the auxiliary battery is already compromised.

How to Diagnose

Diagnosing battery issues in your 2020 Jeep Wrangler requires a systematic approach. Follow these steps to pinpoint the source of the problem.

1. Visual Inspection: Start by visually inspecting both the main and auxiliary batteries. Look for signs of corrosion, damage, or leaks. Check the battery terminals for tightness and cleanliness. A loose or corroded connection can prevent proper charging and cause battery drain.

2. Voltage Test: Use a multimeter to measure the voltage of both batteries. A fully charged 12-volt battery should read around 12.6 volts. A reading below 12 volts indicates a discharged battery. Test the auxiliary battery as well, as it often fails without warning.

3. Load Test: A load test simulates the electrical demands of the vehicle and determines if the battery can maintain voltage under load. Most auto parts stores offer free battery load testing services. This test will reveal if the battery has sufficient capacity to start the engine and power accessories.

4. Parasitic Draw Test: Perform a parasitic draw test to identify if something is draining the battery while the vehicle is off. To do this, disconnect the negative battery terminal and connect a multimeter in series between the terminal and the battery post. A reading above 50 milliamps indicates an excessive draw. Systematically remove fuses one at a time to isolate the circuit causing the drain.

5. Alternator Test: A faulty alternator can prevent the battery from charging properly. Use a multimeter to check the alternator's output voltage while the engine is running. It should be between 13.5 and 14.5 volts. If the voltage is outside this range, the alternator may need to be replaced.

Tools Needed:

• Multimeter
• Wrench set
• Battery terminal cleaner
• Jumper cables (for jump-starting if needed)

Step-by-Step Fix

Addressing battery issues in your 2020 Jeep Wrangler often involves replacing the faulty battery or addressing a parasitic draw. Here’s a step-by-step guide.

1. Jump-Start (If Necessary): If the battery is completely dead, use jumper cables to jump-start the vehicle. Connect the red (positive) cable to the positive terminal of the dead battery and the other end to the positive terminal of the good battery. Connect the black (negative) cable to the negative terminal of the good battery and the other end to a metal ground on the vehicle with the dead battery. Start the vehicle with the good battery and let it run for a few minutes before attempting to start the truck with the dead battery.

2. Battery Replacement: If the battery is failing load tests or is more than a few years old, consider replacing it. Disconnect the negative battery terminal first, followed by the positive terminal. Remove the battery hold-down and carefully lift the battery out of the tray. Install the new battery, ensuring the terminals are clean and the connections are tight.

3. Auxiliary Battery Bypass (Optional): Some owners have chosen to bypass the auxiliary battery altogether to avoid future problems. As tecnic1 stated, "Honestly, just bypass it and be done with it. The aux battery is worse than useless, it's only purpose in life is to die and kill your main in the process." Research the implications of this bypass and consult with a mechanic if needed.

4. Clean Battery Terminals: Corrosion on battery terminals can impede electrical flow. Use a battery terminal cleaner to remove any corrosion from the terminals and cable connectors. Apply a thin layer of dielectric grease to prevent future corrosion.

5. Check and Repair Wiring: Inspect the battery cables and wiring for any signs of damage, such as frayed insulation or broken connectors. Repair or replace any damaged wiring to ensure proper electrical connections.

6. Address Parasitic Draw: If you identified a parasitic draw during the diagnostic process, isolate the circuit causing the drain and repair the faulty component or wiring. This may involve replacing a faulty module, switch, or relay.

7. Alternator Replacement (If Necessary): If the alternator is not charging the battery properly, replace it with a new or rebuilt unit. Disconnect the battery before removing the alternator. Follow the manufacturer's instructions for installation, and ensure the belt is properly tensioned.

8. Test the Charging System: After replacing the battery or alternator, use a multimeter to test the charging system again. Verify that the alternator is producing the correct voltage (13.5 to 14.5 volts) with the engine running.

9. Monitor Battery Health: Keep an eye on the battery's health by periodically checking the voltage and looking for any signs of corrosion or swelling. A healthy battery is essential for reliable starting and electrical system performance.

Parts and Tools Needed

• New battery (Group size specific to 2020 Jeep Wrangler)
• Battery terminal cleaner
• Dielectric grease
• Wrench set
• Multimeter
• Jumper cables
• Replacement alternator (if needed)
• Replacement battery cables (if needed)
• 9v battery

Real Owner Costs

The cost of addressing battery issues in your 2020 Jeep Wrangler can vary depending on the problem and whether you choose to DIY or take it to a shop.

• New Battery: A new battery for your vehicle typically costs between $150 and $300, depending on the brand and type (e.g., AGM battery).

• Alternator Replacement: Replacing the alternator can range from $300 to $600, including parts and labor. The cost will depend on the type of alternator and the labor rate of the mechanic.

• Parasitic Draw Diagnosis and Repair: Diagnosing and repairing a parasitic draw can be time-consuming and may cost between $100 and $500, depending on the complexity of the problem and the labor rate of the mechanic.

• DIY vs. Shop: Replacing the battery is a relatively straightforward DIY job that can save you on labor costs. However, diagnosing and repairing a parasitic draw or replacing the alternator may require specialized tools and knowledge, making it more suitable for a professional mechanic.

Prevention

Preventing battery issues in your 2020 Jeep Wrangler involves regular maintenance and proactive care. Here are some tips to help keep your battery in good condition:

• Regular Battery Testing: Have your battery tested at least once a year, especially before the onset of cold weather. This will help identify any potential problems before they lead to a dead battery.

• Keep Terminals Clean: Regularly clean the battery terminals to prevent corrosion. Use a battery terminal cleaner and apply a thin layer of dielectric grease to protect against future corrosion.

• Avoid Short Trips: Short trips can be hard on the battery because the alternator may not have enough time to fully recharge it. Try to take longer trips periodically to allow the battery to charge completely.

• Turn Off Accessories: Make sure to turn off all accessories, such as headlights, interior lights, and the radio, when the engine is off. These accessories can drain the battery if left on for extended periods.

• Proper Storage: If you plan to store your vehicle for an extended period, disconnect the negative battery terminal or use a battery maintainer to prevent the battery from discharging.

• Check Charging System: Periodically check the charging system to ensure the alternator is functioning properly. A faulty alternator can lead to a dead battery over time.

What Owners Say

Real experiences from JEEP owners:

Owner Experiences

"The recalls, battery replacements and limited range turned off so many people to them. Rivian and hummer(albeit small) took a lot of the market share away from the 4xe" — raining_sheep (source)

"90% of the time it stops working because the aux battery is dead. I wouldn't ignore it." — NotTheUserYouLoking4 (source)

"what happened to me is the aux died and then drained the main battery and i was stuck with a dead 2020 wrangler" — DatesForFun (source)

Lessons Learned

⚠️ "There's no "delete kit" needed . Get under the right front fender well, disconnect, isolate, and secure the battery cables from the auxiliary battery, and pull fuse number 42 (if I remember right) to avoid having that annoying "Service Aux Battery " warning on the dash." — OneleggedPeter (source)

⚠️ "Get under the right front fender well, disconnect, isolate, and secure the battery cables from the auxiliary battery, and pull fuse number 42 (if I remember right) to avoid having that annoying "Service Aux Battery " warning on the dash." — OneleggedPeter (source)

Real Repair Costs

"I’m on my second vehicle with ASS, and also on my second Auto Stop Eliminator. Best $100 you can spend on your jeep." — Thrillhouse74 (source)

FAQ

Q: How long does it take to fix a dead battery issue?

A: Replacing a dead battery is usually a quick process, taking about 30 minutes to an hour for a DIY job. Diagnosing and repairing a parasitic draw can take longer, potentially several hours or even days, depending on the complexity of the issue.

Q: Can I drive with a "service charging system" message?

A: It's not recommended to drive with a "service charging system" message. This indicates a potential problem with the battery or charging system, and continuing to drive could lead to a complete battery failure and leave you stranded.

Q: Is this a common issue on the 2020 Jeep Wrangler?

A: Yes, based on owner reports, battery issues, particularly related to the auxiliary battery, are relatively common on the 2020 Jeep Wrangler. Many owners have experienced problems with the auxiliary battery draining the main battery. As raining_sheep noted: "The recalls, battery replacements and limited range turned off so many people to them."

Q: DIY vs. mechanic – what's recommended?

A: Replacing the battery is a straightforward DIY job that most owners can handle. However, diagnosing and repairing a parasitic draw or replacing the alternator may require specialized tools and knowledge, making it more suitable for a professional mechanic. Consider your comfort level and experience before tackling these more complex repairs.