Problems With Mercedes-Benz GLS: 6 Issues (Explained)

The Mercedes-Benz GLS is a full-size luxury SUV that was introduced in 2006 and shares the same architectural design as the GLE.

This model packs a distinct and clean design, cramped with high-end interior controls.

It is literally also the biggest vehicle of the Mercedes, which automatically means it has a lot of practicality.

However, in the midst of all these impressive features, the GLS also has its own range of known issues. Let’s find out.

1. Failure of the 48V Secondary Battery

The GLS uses a 48v secondary battery to assist the startup of the vehicle and to power other car components.

This battery also allows a gliding function.

For instance, in driving situations that permit downhill glides, the battery, if sufficiently charged, can power the vehicle while the engine shuts itself off.

After this stage, the ISA brings back the engine power.

However, this battery has been reported to randomly stop functioning when the start function kicks in. It was later found out that the car system does not sufficiently charge this battery, leaving it to its random death.

A GLS owner stated in a car review forum that his vehicle gave up just around 5,000 miles. He couldn’t believe it. 

This problem was resolved to an extent when owners cleaned their battery terminals. Some clogged dirt or paint evidently caused the failure of the battery’s terminal.

Some had to replace the batteries, although it was covered by warranty and they had to be newly used or had a low mileage to prove that the fault wasn’t theirs and that it came as a manufacturing flaw.

2. Substandard Interior Quality

The GLS has a disappointing interior build quality, especially for a luxury vehicle that has a starting MSRP of as much as $77,850.

Many owners have complained that the plastic quality was really below par and didn’t meet their expectations.

Some owners stated that their folding rear seats got damaged easily after some usage. Other folks expressed their dislike for the cheap quality of the dashboard.

There wasn’t any trace of sleekness and polished finish to their interior quality. Highly disappointing.

You can also explore the best and worst years for the Mercedes-Benz GLS.

3. Foul Smell From the HVAC

This issue was predominantly found in vehicles produced in the 2010 models and it was reported that an odor came from the AC of the vehicle whenever they activated it.

Some folk stated that about 6,000 miles they started getting this smell and it was nothing as they have ever experienced before.

It was also noted that after changing the air and cabin filter, there was no change to this problem.

This complaint was so bad that it eventually led to a lawsuit against the company that they had to settle.

It was later found that a clogged mold inside the vehicle’s evaporator because of condensation caused this foul smell.

This evaporator was located close to the dashboard, which gave a lot of room for the mold to grow.

A simple fix is to spray disinfectant down the vents, but this is no permanent guarantee that it will clear it out. Another option is to take down the entire HVAC system and do a thorough washing.

However, this is not a simple fix, as it can be very tiring.

4. Vibrations in the Vehicle

Vibrations in the GLS were another problem that plagued the vehicle and unsettled owners.

These vibrations became very noticeable when the car was traveling at speeds over 60 miles per hour, especially with models that came with bigger wheels.

Owners complained that their tires were unbalanced, and it affected the total handling and control of the vehicle.

This vibration also came pretty early as a consumer stated that he had only driven the car for 50 miles when he began to notice this vibration.

Many reasons can cause these vibrations. Some of them include unbalanced wheels, axle problems, loose steering compartments, bad tires, damaged wheels, worn-out suspension, and faulty wheel bearings.

All things being equal, these problems are supposed to show up in older vehicles or cars that have been used for a while, but some GLS owners stated that they experienced this problem just after they purchased it.

There are several ways to mitigate the effect of vibration in a vehicle. The first step is to rotate your tires. This evens out the wear and maintains the threads on the tires for better usage.

Also, you can improve the handling of your vehicle by using a smaller wheel but with tires that had larger sidewalls.

Another important check is to perform wheel alignment, road force balancing, and even suspension checks.

Although, most owners stated that they had to make a complete replacement of the tires, using another brand before these vibrations could flatten out.

It was assumed that the standard tires that came with the vehicles were below standard, hence the vibrations.

5. Excessive Tire Wear

Coming from the vibrations problem, it is evident that the GLS standard tires were subpar, and they were susceptible to wear too quickly.

Owners stated that they had to do a tire change at just 10,000 miles.

While this is understandable for the high-performance models but this problem seemed to plague their standard models as well. The major causes for tire wear in the GLS include:

• Bad wheel alignment 
• Over-inflated and under-inflated tires
• Worn-out steering
• Faulty suspension geometry 
• A bent rim

However, repair shops found out that the main reason for this. was suspension geometry as they lacked camber or caster adjustments.

Caster is simply the angle of each wheel while camber defines how your tires lean to the ground. Camber affects your tires the most.

Also, the GLS was a full-sized SUV that weighed almost 6,000 pounds and the AMG models are equipped with revving engines that can quickly chew into the quality of these tires.

To overcome this problem, it is advised to rotate your tire as often as possible to extend its life. It is also recommended that you align your wheels as needed.

However, this should be done by a professional, so that it won’t cause damage to your factory settings. Last, you can use tires with bigger threads to accommodate the high traction force of your vehicle’s engine.

6. Poor Headlights

Weak Headlight was a common problem that plagued the Mercedes Benz. Not only does the GLS suffer from this issue, but other models also are not excluded.

The halogen lights are not sufficiently bright to see the road at night and owners have protested that it affects them. Other vehicles that had brighter headlights often overshadowed theirs easily.

Unfortunately, the brighter headlights only came as an available option for those that drove the first generation of the GLS. Thus, to rectify this issue, they had to buy it.

However, the general fix to this problem for anyone who suffered from this issue was to replace the stock bulbs with brighter ones that also had a higher color temperature. This is literally the cheapest and safer option.

Consumers can also decide to upgrade their headlights to retrofit LED bulbs.

However, this is a bit more technical and intricate and so, it requires the hand of a professional because it needs so much rewiring and reprogramming of the vehicle’s electric system. Unless you’re a professional, do not attempt DIY.

Meanwhile, you can also explore some problems with Mercedes SUVs.

General Pros and Cons of the Mercedes-Benz GLS

If you plan to buy the GLS, it is best to know its functionality and its weakness to make the proper and detailed decision. Below is the list of pros and cons of the GLS.

Pros

• Smooth and revving engines
• Standard ride quality
• Decked out interior
• Spacious and luxurious cabin
• Impressive cargo space
• High-end interior controls and driving aids

Cons

• Unimpressive fuel economy 
• Pricey options
• Minor glitches with the interior controls 
• Expensive dealerships rates

What Is the Resale Value of the Mercedes-Benz GLS?

According to Caredge, the Mercedes-Benz GLS-Class has a depreciation value of 62% after 5 years and a resale value of $44,047 after a 5-year period.

If you aren’t considering buying the GLS, the good news is that the GLS is among the Mercedes models you can lease.

Below is a table highlighting the depreciation value and the resale value of the Mercedes-Benz GLS.

What Do the Reviews Say?

According to Auto Express, the GLS took a tremendous leap from its predecessor as it now reeks of superb comfort, performance, and technology. 

It has a strong and refined diesel engine and its smoothness gets better with its air suspension that cushions out road bumps and imperfections.

For car enthusiasts, you can opt for the higher trims the Advanced E-Active Body Control suspension set-up.

It employs two cameras to check out for any road bumps and avoid them just in time.

Lastly, the interior of the GLS is an excellent place to spend time as the build and placement of the controls are nicely put.

The Benz rivals the likes of

• The BMW X7
• Infiniti QX80
• and the refurbished Lexus LX 600

Although they beat it in terms of cabin space, the GLS covers up for this with its sophistication.

Go Back: Problems for all Mercedes models.

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ⓘ  The information in this article is based on data from National Highway Traffic Safety Administration (NHTSA) recall reports, consumer complaints submitted to the NHTSA, reliability ratings from J.D. Power, auto review and rating sites such as Edmunds, specialist forums, etc. We analyzed this data to provide insights into the best and worst years for these vehicle models.