Jeep Commander Bad Alternator Symptoms: How to Check Voltage

ByChalobah Leonard Jeep

The Jeep Commander is a powerful and reliable SUV, but like all vehicles, it can have its fair share of issues. A faulty alternator is one of the common problems with the Jeep Commander. Owners of Jeep Commander will be worried now about Jeep Commander’s bad alternator symptoms: how to check the voltage?

Symptoms of a bad alternator in a Jeep Commander include dimming headlights and interior lights, slow operation of electrical components, and stalling or misfiring of the engine. To check the voltage, use a multimeter to measure the battery’s voltage. The reading should be between 13.2 and 14.4 volts.

In this guide, we will go over the key symptoms of a failing alternator in the Jeep Commander and how to check the voltage to determine if it is indeed the source of the problem.

Symptoms of a Bad Alternator in a Jeep Commander

A bad alternator in a Jeep Commander can cause several issues, some of which can be difficult to diagnose. Here are some of the most common signs and symptoms of a bad alternator in your vehicle:

1. Warning Light

A warning light for a bad alternator in a Jeep Commander may display a battery symbol or an alternator symbol on the dashboard. Other symptoms of a failing alternator include dimming or flickering headlights, slow cranking or difficulty starting the engine, electrical system malfunctions such as power windows or door locks not working, and warning lights for low voltage or battery issues.

2. Dead Battery

Dead battery is one of the symptoms of a bad alternator in a Jeep Commander. This happens because the alternator is responsible for charging the battery and maintaining the vehicle’s electrical system. For faulty alternators, the battery will eventually lose its charge and the vehicle will not start. Other symptoms of a bad alternator include dimming or flickering lights, flickering gauges, and an illuminated check engine light.

3. Dimming or Flickering Lights

Dimming or flickering lights in your Jeep Commander is a symptom of a bad alternator. The alternator is responsible for charging the battery and providing power to the electrical components of your vehicle. If the alternator fails, it may not be able to keep up with the demand for electricity, resulting in flickering or dimming lights.

4. Slow Engine Start

Slow engine start can be a symptom of a bad alternator in a Jeep Commander, as the alternator is responsible for providing power to the vehicle’s electrical system and starting the engine. If the alternator fails, it can cause the battery to lose its charge, leading to a slow or no engine start. Other symptoms of a bad alternator include dimming lights, dead battery, and flickering gauges.

5. Engine Stalling

Engine stalling in your Jeep Commander is a sign of a bad alternator. The alternator supplies power to the battery and other electrical components while the engine runs. If the alternator is not functioning correctly, it causes the battery to lose charge, leading to engine stalling. Other bad alternator symptoms in a Jeep Commander include dimming lights, warning lights on the dashboard, a dead battery, and a grinding noise when starting the engine.

5. Whining or Grinding Noises

Whining or grinding noises are common symptoms of a bad alternator in a Jeep Commander. The alternator is responsible for charging the battery and providing power to the vehicle’s electrical components. When the alternator fails, the battery will not receive a charge, and the vehicle may experience electrical problems, such as dimming or flickering lights and the radio shutting off.

How to Check Voltage in Jeep Commander?

Checking the voltage will help you determine if your Jeep is running properly and the electrical system is functioning correctly. Here are some tips on how to check the voltage in your Jeep Commander.

Step 1: Check Voltage with a Multimeter

To check the voltage of your Jeep Commander using a multimeter, follow these steps:

  1. Turn off the ignition.
  2. Set the multimeter to the “DC voltage” setting.
  3. Connect the multimeter to the battery terminals or a component to be tested; positive leads to positive and negative leads to negative.
  4. Read the voltage on the multimeter display. A healthy battery should read between 12.4 and 12.7 volts.

Note: It is important always to follow safety precautions when working with electrical equipment. You should wear protective gear and avoid touching any live wires or terminals.

Step 2: Testing the Battery

Using a digital multimeter, you can test the battery voltage in a Jeep Commander. Here are the steps to follow.

  1. Turn off the vehicle and make sure all electrical accessories are turned off.
  2. Connect the positive lead of the multimeter to the positive battery terminal and the negative lead to the negative terminal.
  3. Switch the multimeter to the DC voltage setting and record the reading. A healthy battery should read between 12.4 and 12.7 volts.
  4. Start the vehicle and take another reading. A healthy battery should read between 13.7 and 14.7 volts when the engine is running.
  5. If the readings are below the recommended levels, it may indicate a weak battery or an alternator problem. In this case, it is recommended to have the battery and alternator tested by a professional.

Note: Always wear protective gear when working with a battery, such as gloves and safety glasses, to avoid any electrical shock or acid burns.

Step 3: Testing the Alternator

For testing the alternator voltage in a Jeep Commander, you will need a multimeter and some basic knowledge of electrical systems. Here is a step-by-step guide to help you test the alternator:

  1. Turn off the engine and disconnect the battery.
  2. Connect a multimeter to the battery terminals and set it to measure DC voltage.
  3. Start the engine and take note of the voltage reading. It should be between 13.5 and 14.5 volts.
  4. Check the voltage while the engine runs at different RPMs and note any changes.
  5. Turn on all electrical accessories such as lights, air conditioning, and radio to see how they affect the voltage reading.
  6. Disconnect the alternator and measure the voltage again. It should be close to 12.5 volts.
  7. Inspect the alternator’s output with a load tester to see if it’s producing the correct amount of power.

Note: Testing the alternator voltage in a Jeep Commander is a simple process that can be performed with a multimeter. By following these steps, you can ensure that your alternator is functioning properly and charging the battery.

Step 4: Verifying the Connection

To verify the connection to check the voltage in a Jeep Commander, follow these steps:

  1. Locate the battery under the hood.
  2. Connect a multimeter’s positive lead to the battery’s positive terminal.
  3. Attach the multimeter’s negative lead to the battery’s negative terminal.
  4. Turn on the multimeter and set it to measure voltage.
  5. Read the voltage displayed on the multimeter. The voltage should be between 12.5 and 14.5 volts.
  6. If the voltage is outside of this range, there may be an issue with the battery or charging system.
  7. Turn off the multimeter and disconnect the leads.

Final Words

Failing alternators in a Jeep Commander can exhibit various symptoms, including dimming lights, dead battery, unusual sounds, and warning lights on the dashboard.

To check the voltage, you can use a multimeter to measure the battery voltage while the engine is running. If the reading is less than 13.5 volts, it may indicate a problem with the alternator. Regular maintenance and timely diagnosis can prevent more serious issues and keep your Jeep Commander running smoothly.