Mercedes EQS Won’t Charge – This is Why!

The Mercedes Benz EQS is everything you expect from Mercedes, but it’s useless if it won’t charge. I’ve been a mechanic for 25-plus years. Let’s get you charging.

Top reasons your Mercedes EQS won’t charge include:

  • Fault in the cable
  • Connection fault
  • Temperature error
  • Account connection fault
  • 12V Battery flat

This article will examine why your Mercedes EQS is not charging and how to solve the problem.


Fault in the Cable

Charging your Mercedes EQS can be done in one of three ways:

  • Level 1
  • Level 2
  • Level 3

Level 1 charging is done using a standard 120V household plug, but it can take up to 24 hours plus to charge your EQS, so not at all practical.

Level 2 requires a specific Wall Connection (installed by an electrician) that has 240V and will charge your EQS overnight for approximately 8 hours.

Level 3 charging is fast charging which can only be achieved at a fast-charging DC station such as Electrify America.

In saying all this, we generally only run into cable problems when using a Level 1 or Level 2 at home.

Charging cables are strong, sturdy plastic but can still become damaged. Unfortunately, the main culprit for damage is your Mercedes wheels. Your EQS comes in at a whopping 6900 lbs. That’s a lot of weight for your cable to cope with.

Your charging cable has four lights on it. From the top down, they are:

  • Supply indicator
  • Charging indicator
  • Temperature monitor
  • Safety system

For everything to be ok, the Supply Indicator must be white. If the bottom light is flashing Red, there is a cable malfunction. The first thing to try is a cable reset to correct it.

You can do this by disconnecting from the car and the mains. Wait approximately 5 minutes and reconnect.

If the problem persists, the cable is faulty and should be replaced.

There may be a visible break or damage in the cable, or it might be damaged internally. Either way, it is not advisable to continue using it, and you should never try to repair the cable. The cable carries up to 240V and can cause serious injury.

Contact your Mercedes dealership to order a new one.

Connection Fault

The fault might not be your cable but, in fact, the connection between your cable and your EQS. There are a couple of reasons why the connection could be failing.

  • User error
  • Fault at the wall
  • Fault in the car

User Error

User error is one of the main reasons your Mercedes won’t charge after ruling out cable fault. The charge cable must be connected to your car correctly, without strain or tautness.

As you plug your cable into the onboard computers, check for a complete seal between the wall and the car. A strain in the cable can prevent this, and charging will not commence.

If necessary, move the car nearer to the charging connection.

Fault at the Wall

Another reason is there is a fault in the wall connection. This could be due to age or a general fault. EV owners are increasingly prevalent; many are on their second EV or have purchased the Mercedes EQS as an additional car.

If you already have an EV, you will likely already have a wall connection. Many home chargers are Chargepoint Home Flex, using the universal J1772 connector. They work with brands such as Nissan, Kia, Chevrolet, and your new Mercedes EQS.

However, depending on use and make, connections don’t last forever (approximately 5-8 years).

If your wall connection is giving trouble and has some age, it might be time for an upgrade! Your selection will depend on whether there are other EVs in your household. You will have to choose one that is compatible with all.

I recommend Chargepoint as they have paired with Mercedes Benz and Qmerit (electricians). They offer a 3-year warranty, which is more than most, and have a support network.

If, on the other hand, your EQS has replaced an EV and your wall connection is having trouble, I would recommend the Mercedes Wallbox. This is specifically designed to charge your Mercedes EQS; it can deliver 11kW of power and can also be utilized by other EV brands if you were to add to your household in the future or have someone staying over with an EV.

To me, it makes sense to go with the Mercedes recommendation. An upgrade in the pipeline offers 22kW, which is currently only available in certain European countries (Sept 22) but hopefully will be rolled out in the USA shortly.

Fault in the Car

Not only do you have indicator charge lights at the wall, but also your charge point on your EQS.

Charging in progress is Blue Lights flashing on either side of the plug. Solid Blue Lights indicate charging is complete. The one to be concerned about is Flashing Red, a vehicle malfunction.

You can check the cable by unplugging everything and doing a quick visual. Check to see if there is damage to the pins or debris in the socket.

If there are any foreign objects in the socket, try and gently remove them. If your cable lives outside, there’s the possibility of leaves or even small bugs getting into the socket. The bugs are attracted to the heat but can play havoc with your charging as a complete seal can’t be made.

Before trying to clean anything, ensure everything is unplugged. Only use a soft brush or a vacuum to remove the debris.

It’s advisable to contact Mercedes if you are having Red Light issues.

Temperature Error

The charging unit has, as previously mentioned, four lights. The 3rd light is a temperature indicator.

This is the temperature of the unit. The nature of charging and high-voltage electricity means that cables can get hot.

If the temperature light flashes Red along with a Green flashing light, the connection is Over Temperature, and charging will be reduced but not stopped.

If there is a Red light without green, the unit is too hot and charging can’t be completed. It will not commence until the unit has sufficiently cooled. This can also be affected by the unit being in direct sunlight, where the sun is overheating the unit.

EV charging of any brand doesn’t like being too hot or cold. It affects the ability to charge correctly. Mercedes has a Pre-Entry Climate Control, which will warm the batteries to a safe temperature before charging begins. Too much heat applied to cold Li-Ion batteries can kill cells and degrade the high voltage battery over time, meaning a full charge can’t be achieved in the future, but only a 70-80% charge.

You can activate Pre-Entry in the car using the MBUX screen by selecting a Departure Time or using your Mercedes app on your smartphone.

Account Connection Fault

All the charging issues we’ve touched upon so far are charging at home, but what if your Mercedes EQS won’t charge at a fast charger? This can be a real pain, but the solution is usually simple.

When you purchase your Mercedes EQS, you are entitled to two years of free 30-minute charging at all Electrify America stations.

But this has been known to give some users trouble at the start.

It’s all to do with how you set up your account.

Your Mercedes dealer will talk you through your Mercedes Me account, but it’s important to note that you must activate your Electrify America account through your Mercedes account and not through a separate EA app.

Many Mercedes EQS owners have set up an EA account, thinking they are good to go with their free 30 minutes, only to find they are being charged for their top-up.

It only works if you set it up through your Mercedes account, and even at that can take a couple of days to kick in. You can’t avail of the free EA charging until you receive a notification email to your account.

If you are having problems at an Electrify America station, you can call their customer service number, listed on all chargers, along with the charger ID number. Don’t disconnect your cable before calling them, as reconnecting can incur a charge.

There might just be a problem with the particular charger you are at, and they will recommend that you switch to another, or it could be as simple as the ambient temperature is too cold, which can take longer to charge your car than the allocated 30 minutes. You should be good to go if you can at least reach 80% in the 30 minutes.

12V Battery Flat

The last thing we’ll consider as a reason your Mercedes EQS won’t charge is that your 12V Battery is flat. All EVs have a high-voltage battery but also a traditional 12V battery. The 12V manages items like locking, windows, wipers, etc. Ordinarily, you can hook up a booster to the 12V and return to the road.

However, Mercedes EQS owners have no access to the 12V, or indeed access to under the hood at all. An elaborate cooling system prevents bacterial particles, CO2 emissions, or anything harmful from entering the cabin, and Mercedes doesn’t want you playing with it. Only a registered Mercedes Technician is authorized to open the hood.

But there must be a way, I hear you say! And yes, there is; if you check out YouTube, there are examples of gaining access. But beware, if you open the hood, Mercedes have warned that you will void your warranty – 4 years or 50,000 miles. The onboard computer will know that an unauthorized hood opening has occurred.

So what to do if your battery is flat? The only solution is to call Mercedes Customer Service, and they will send a technician out to start your car.

If you are curious about other EV models, check out the EV FAQ category.

John Cunningham

John Cunningham is a technical writer here at He's a Red Seal qualified Auto Service Technician with over twenty-five years experience working on Classic and Modern Cars. He's worked for GM, Jaguar, Land Rover, Volvo, Audi, and VW main dealers.

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