bmw battery head trunk won't open how to jump start

How to jump start a BMW Dead Battery

Updated Tuesday Feb 06, 2018

how to jump start a bmw with dead battery Is the car battery in your BMW dead? In this guide, you will learn how to properly jump start a BMW battery. Common causes and symptoms of dead BMW battery. Including you can't start the car, unlock the doors or the trunk. Follow the instructions below to learn how to properly jump start a BMW. 

You don't need to access the battery in the trunk to jump start a BMW. Read these instructions to learn how to properly jump start a BMW.

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1. Symptoms of Dead BMW Battery

Common symptoms that you may experience if your BMW battery is dead.

  • BMW won't start
  • Can't unlock car
  • Lights too dim (Check headlights)
  • BMW turns over slowly
  • Slow engine crank
  • Dashboard Warning Lights on
  • Can't start the car with Push Start button
  • Engine cranks slowly then stops
  • Click, Click, Click noise
  • Electrical Issues
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2. Warning

  • Never jump start a BMW by connecting jumper cables to the battery located in the trunk. Always use the terminals in the engine compartment which are designed for jump starting a BMW. See instructions below. 
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3. What you will need

To jump start a BMW you can use jumper cables or a jump starter box. 

  • Jump Starting a BMW using Jumper Box
    jump starter for bmwThe safest way to jump start a BMW is to use lithium jump starter such as the NOCO GB40 1000 Amp jump starter. The NOCO GB40 provides 1000 cranking amps which is enough to jump start even a V8 BMW gasoline engine. Most importantly it provides backward connection warning and reverse polarity protection. Most jump starters don't provide any protection if you connect them backward which could end up costing you thousands of dollars in damage to electronic components. These ultra safe jump starters are designed to avoid just that.
  • Jump Starting a BMW using Jumper Cables
    The second option to jump start a BMW is to use a car that's running and jumper cables. Since BMW typically have large engines and draw high current, it is recommended to use 4 Gauge Heavy Duty Jumper Cables which are thicker and allow more current. 6 gauge cables will work as well but they may get hot if you crank the engine for a long time. 

Regardless of which method you use to start your BMW, always connect to the positive and negative terminals in the engine bay. Never connect to directly to the battery located in the trunk. Even when using jumper cables to jump a BMW with a dead battery.  

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4.  Instructions on how to jump start a BMW

Follow these instructions to jump start a BMW. These instructions work on all BMW models including 1-series, 2-series, 3-series, 5-series, 6-series, 7-series, X1, X5, X6. It is important to follow the proper procedure to jump start a BMW. If you don't or jump start a BMW by connecting jumper cables to the battery located in the trunk you can cause electrical issues. 

  1. Remove the metal blade from your BMW key fob. 
  2. Use the metal key to manually unlock the driver's door. how to jump start a bmw with completely dead battery


  3. Pop the hood open by pulling the hood release under the dashboard. jump start bmw 1 3 5 6 7 series  x1 x3 x5 x6


  4. Release the hood safety latch at the front of the hood. bmw battery dead diy jump start instructions locked trunk
  5. Locate the terminals in the engine bay designed to jump start your BMW. bmw how to jump start if you can't get into the trunk


  6. Connect the red (positive) jumper cable to the positive terminal. bmw positive terminal location


  7. Connect the black (negative) jumper cable to the negative battery jump starting location


  8. Start the BMW. Watch the video on how to jump start a BMW. 
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5. How to get into the trunk, if you have a dead battery

Many BMW owners ask how do I get into the trunk if the BMW battery is dead.

Wait! Why are you trying to access the trunk? Are you trying to find this? 

bmw battery dead trunk won't open

If your BMW battery is dead, your trunk won't open. 

BMW engineers have made it difficult to get access to the trunk when the battery is dead. You don't want and shouldn't jump start a BMW directly from the battery. This is a common mistake many road side assistance technicians make. If you read on BMW forums you will find hundreds of cases where control modules were damaged by improperly jump starting a BMW. Costing car owners thousands of dollars in repair. 

If you have a good reason to get in the trunk but the battery is dead this is what you should do.

  1. Manually unlock the car. 
  2. Open the hood. Yes, open the hood first. 
  3. Connect a 12-volt source at the positive and negative terminals under the hood.
  4. Now that your BMW is powered up, press the trunk unlock button on your key fob. 
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6. How to bring a BMW battery back to life

Is your BMW battery is completely dead? Replacing the battery on a BMW is expensive because not only do you need a new battery, but it also needs to be registered. The typical cost of BMW battery replacement range in the $400-$500. Before you spend hundreds on a new battery we recommended to use a 12 volt trickle battery charger to bring the battery back to life instead of jump starting the car and letting the alternator charge the battery.

how to charge a bmw battery

By trickle charging a dead BMW battery, you have a better chance of bringing the battery back to life. Otherwise, your BMW may no longer hold a proper charge. Use the OEM BMW Battery Charger or even the cheaper Black+Decker BBM3B 12V Battery Charger Maintainer which works just as well. It will take at least 24 hours to bring a completely dead battery back to life. You are only providing 2 Amperes to the battery which is a slow charge but ensures no damage is caused to the battery cells.  

Watch the video on how to charge a BMW Battery. 

Don't leave the keys in the ignition as your BMW charges. 

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7. BMW Battery Keeps Dying

If your BMW keeps on dying or is not holding a proper charge it could be due to any of the following: 

  • Battery Age / Old Battery
  • Corroded or Loose Battery Connections
  • Parasitic Current Drains in the electrical system
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8. How to replace a BMW battery

If your BMW is over 7 years old you are driving in borrowed time. Sooner or later you will need to replace the battery. Don't panic! You can replace a BMW battery yourself. Just make sure to perform battery registration procedure. Here is a list of articles that will help you replace a BMW battery. 

We hope that you found these instructions helpful. If you have any tips or advice that will contribute to this article, add it in the comments section below. 

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Posted by David on Aug 29, 2017 @ 22:24 pm

Posted by tafa on Apr 17, 2018 @ 22:02 pm

Posted by swiftbatteryspecialist on Jun 22, 2018 @ 02:39 am