Is your Mercedes-Benz battery dead? Do the lights turn on at all? Click…Click…Click.. is all you hear when you try to start your Mercedes-Benz? The problem is frequently a dead battery. Improper jump-starting a Mercedes-Benz can cause electrical or control unit problems which can become expensive repairs. In this guide, we will show you different methods by that you can safely jump-start your car and get back on the road. You have three options to get your car running again. When the battery is completely dead, you will know as nothing on the car turns on. The battery could be partially discharged, so you will hear the clicking, as shown in the video clip.
When the battery is completely dead, you will know as nothing on the car turns on. The battery could be partially discharged so that you will hear a CLICK… CLICK… CLICK.. as you try to start your Mercedes-Benz.
First, locate the jump-start connection points to ensure you jump-start your Mercedes-Benz correctly and not damage any electrical components. If your Mercedes-Benz doesn’t have the jump start connection points, you must connect directly to the battery. The battery is located in the trunk, engine bay, under the front passenger seat, or the rear passenger seat. Location of jump-start connection points on Mercedes-Benz C S E GL CLA SL Class
Three (3) ways to jump-start a Mercedes-Benz
Here are your options on how to get the car running again.
If you need to return to the road quickly, you can start the car using jumper cables. The problem with this method is that if the battery is completely dead, jump starting can shorten the life or even damage the battery. It can also cause electronic components in the car to malfunction and trigger under voltage fault codes for the control units in your Mercedes-Benz. The best option is to use a battery charger if possible. It will take longer, but you can save the battery and not damage your car’s electronics.
- Use jumper cables and another car.
(Higher risk. May trigger under voltage fault codes in control units.)
- Use a booster starter jump box (Recommended to keep the jump box connected for 15 min after the start.)
- Charging the battery using a battery charger (Best method)
Here is the instruction on jump-starting your Mercedes-Benz by applying these methods.
- When you jump start a car do not allow the clamps to touch each other or the car frame.
- To avoid damaging the electrical components of your Mercedes-Benz, it is recommended to use the jump-starting terminals found in the engine bay whenever possible.
- If your battery is completely dead, remove the metal blade key from your keyless remote and use it to unlock the driver’s door or the trunk.
Method 1 Jump start Mercedes-Benz battery using jump cable.
- Get your jumper cables out. Most owners already have a set of jumper (BOOSTER) cables. If you don’t have jumper cables, you can order them on Amazon. We recommend buying cables with a low gauge rating, which means thicker wire. Here is a list of Best Selling Booster cables on Amazon.
- Bring the helper car next to your Mercedes-Benz. You can have both cars face each other. If there is enough room, park the cars parallel to each other.
- Set the emergency brake. Place both cars in the park and set the parking brakes.
- Open hood. Open the hoods of both cars. If you are having difficulty opening your Mercedes-Benz hood, read our post How to Open a Mercedes-Benz hood.
- Turn the helper car off. Remove the key from the ignition of your Mercedes-Benz ignition as well.
- Locate the battery on the helper car. Connect the jumper cables to the helper car. Be careful not to allow the two clamps to touch together.
- Connect the clamps to the Mercedes-Benz jump-start terminals. Current models of Mercedes-Benz are equipped with jump-start terminals. Attach clamps directly to the battery if you don’t have the jump start terminals.
- Connect the POSITIVE clamp to the positive terminal of the helper battery. The positive clamp is generally red. The battery will have a + sign or the letters POS written next to the terminal.
- Connect the other POSITIVE clamp on the other end of the booster cables on the Jump Start Terminal of your Mercedes-Benz.
- Connect the NEGATIVE clamp on the negative terminal of the helper car.
- Connect the NEGATIVE clamp on the ground terminal of your Mercedes-Benz or any part of the engine or frame that is not painted.
MAKE SURE THE RED CLAMP DOES NOT TOUCH THE CAR FRAME OR THE BLACK CLAMP.
- Start the helper car. If someone is helping you, have them rev up the engine to around 2000 RPM. If that’s not possible, let the helper car idle.
- Get inside your Mercedes-Benz and start it. If it doesn’t start immediately, let the battery charge for at least 5 minutes, or even longer if possible.
- If your Mercedes-Benz refuses to start, see the Troubleshooting FAQ section below.
- Once the car starts, disconnect the cables. Begin by disconnecting the negative battery cables on both cars.
Caution: Your Mercedes-Benz’s electrical systems can get damaged, or the control units will trigger under voltage fault codes if you let the car run while connected to a dead battery.
Note: Jump-starting a car with a fully discharged battery will shorten the life of the battery or damage the battery.
Hint: For a safer method to jump-start a Mercedes-Benz with a fully discharged battery see Method 3.
Method 2 Jump start your car battery with a booster pack/jump starter box.
- Get a jump box that is powerful enough to turn over a Mercedes-Benz engine. Generally, it would be best to have a jump box with 1000 peak amps or more. The best jump starter that is very practical and portable and will start your Mercedes-Benz is the NOCO 1000 Amp 12 volt Lithium Jump Starter, shown in the picture below. They also make a 2000 amp portable power bank that will jump-start the car easily but is more expensive.
- Set your Mercedes-Benz shifter in the park and press the parking/emergency brakes.
- Turn the car off. Remove key from the ignition.
- Open hood. If you have difficulty opening your Mercedes-Benz hood, read our post How to Open a Mercedes-Benz hood.
- Locate Jump Start Connection Terminals. If you need help, look at the pictures at the beginning of this article.
- Connect the buster jump box cables to the positive and negative jump start terminals below.
- Connect the Positive (+) red jump box clamp to your Mercedes-Benz jump start terminal. The jump start terminal is typically covered with a red plastic with the Plus (+) sign on top. If you don’t have jump start connection points, connect to the battery as follows.
- Connect the black Negative (-) clamp to the negative ground post on the frame. If you can’t find the negative terminal, you could also connect the negative clamp to the vehicle’s metal frame.
- If your jump box has an ON switch, turn it to ON. Many jump starter boxes don’t have an ON switch.
- Turn the ignition to position 2, and all dash lights will be on but do not start the car. Turn off your lights and all other vehicle accessories.
- MAKE SURE THE RED CLAMP DOES NOT TOUCH THE CAR FRAME OR THE OTHER CLAMPS.
- Get inside your Mercedes-Benz and start it. If it doesn’t start right away, WAIT 2 MIN and try again. Wiggle the clamps to ensure they are making proper contact at the terminals. Make sure all your lights and accessories are turned off.
- If your Mercedes-Benz doesn’t start, see the Troubleshooting FAQ section below.
- Once the car starts let the jumper box be connected for at least 10 minutes or more if possible. Disconnect the jumper box. Disconnect the NEGATIVE clamp first.
Method 3 Jump Start – Use a battery charger
Charge the battery using a 10 AMP charger.
Safe method to start your Mercedes-Benz.
Advantages of using this method:
- Less risk of damaging your car’s electronics.
- Slow charging the battery usually restores the battery to its previous condition with minimum impact on the battery life.
- Control units will not set low voltage fault codes on your Mercedes-Benz control units.
Disadvantage: It will take several hours to charge the battery fully.
How to Start Mercedes-Benz using a battery charger.
- Find a 12-volt battery charger designed to slow charge the automotive batteries. The charger needs to provide at least a current of at least 2 AMP up to 12 AMP. We would recommend a charger that monitors the battery and provides efficient charging while avoiding overcharging such as the Black and Decker Battery 12V 2 Amp Charger which works on Mercedes-Benz AGM, GEL and WET batteries. Or if you need a battery charger that will charge the battery faster, take a look at Schumacher SpeedCharge 3/6/12 AMP Charger-Maintainer-Tester, and use the 12 AMP setting.
- Set the emergency brakes and turn your car off.
- Locate the battery on your Mercedes-Benz. Depending on the model, it is either on the engine bay, or typically on the passenger side. Under the rear seat. Or in the trunk, next to the spare tire.
- It is recommended that you DISCONNECT the negative battery terminal before you start charging the battery.
- Connect the battery charger.
- Connect the POSITIVE clamp on the battery’s positive (+) terminal. The positive clamp is red. The battery will have a + sign or the letters POS written next to the terminal.
- Connect the NEGATIVE clamp on your Mercedes-Benz battery’s negative (-) terminal.
- Let your car charge. It will take several hours for the battery to fully charge. If you are using the Black and Decker battery charger mentioned above, you will know when the battery is fully charged and when the LED light on the charger turns solid green. A fully discharged battery can take up to 24 hours to charge.
- Remove the battery charger and connect the Negative terminal. Make sure to tighten the bolt, and that the clamp is not loose on the battery post.
- Start your Mercedes-Benz.
This is the safest method to get your Mercedes-Benz started again. It will not shorten the battery life. It is less likely that you will damage the car electronics too.
The only drawback is that you will need several hours and in some cases up to two days to fully charge the battery completely.
We would recommend that you keep the jumper box connected for at least 15 minutes after the car starts. This will avoid damaging any of the car’s electrical systems by running the car with a fully discharged battery.
Frequently Asked Questions
How do I know which is the POSITIVE + terminal?
- It will have a RED cover.
- It may have the symbol + next to the battery terminal.
- You could also have the letters POS written near the positive terminal.
How do I know which is the NEGATIVE – terminal on my battery?
- It will have the writings Neg, Negative or –
- The negative terminal post is shown on a Mercedes-Benz
All I get is Click Click Click……
The common cause for this problem is a discharged battery. The battery may have enough electricity to turn on the lights in the car but not enough to start the car. I can’t find the termnial to jump-start my Mercedes-Benz. Most Mercedes-Benz cars, especially the newer models have jump-start connection points. They are in the engine bay. The positive terminal is shown in red. Here is an example.
Here is an example. If you can’t find these terminals you may need to jump-start them by connecting directly to the battery.
How long should you crank the engine during a jump start?
Do not crank the engine for more than 5 seconds at a time. Wait 30 seconds and try again. If your car doesn’t start after 3 or 4 tires, you must look at other possible problems.
How to jump-start a Mercedes-Benz with the trunk locked?
You have two options.
- You can remove the metal key from the key fob and unlock the trunk.
- Connect a 12v battery source such as jumper cables, a jump box, or a car battery charger to the Jump Box Connection points. This will power up the car, and you will be able to unlock anything.
Where are the jump terminals on an S-Class?
In the W220, the jump-start terminals can be accessed under the passenger footwell. Remove the passenger side carpet and cover.
The newer models have jump-start connection points in the engine compartment.
Where is the battery located on a R350 R500 R Class Mercedes-Benz?
The battery is located under the front passenger seat.
Here are the instructions on how to replace the battery.
VIDEO How To Jump Start A Car Battery
What will I need to jump-start my Benz?
As mentioned in this article, you will need a jumper cable set, use a jump booster pack, or charge the battery using a charger/maintainer. These are the most common items used to jump start a car.
- Failure to follow proper directions can damage control units and electronics.
- Do not lean over the battery when you connect the clamps if you are connecting directly to the battery.
- Fully discharged batteries should be monitored during charging to prevent overheating if they are disconnected and replace the battery. Otherwise, there is a high risk the battery could explode.
Keep flames or sparks away from the battery, and avoid improper connection of jumper cables.