2020 Mercedes-Benz S65 AMG Heater Isn't Working

Fix Heater Issues in Your 2020 Mercedes-Benz S65 AMG

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Reviewed by
Andrew Hajjar
Written by RepairPal Car Genius
Updated January 14, 2025
0%
31% chance it's the
Heater Blower Motor
0%
18% chance it's the
Heater Blower Motor Resistor
0%
51% chance it's
Something else
The most common reasons a 2020 Mercedes-Benz S65 AMG heater isn't working are a broken heater blower motor, a problem with the thermostat, or a failed heater blower motor resistor.
  • Heater Blower Motor: A faulty heater blower motor can result in inadequate airflow or no air circulation in the cabin, affecting the heating system's performance.
  • Heater Blower Motor Resistor: A faulty heater blower motor resistor can cause inconsistent fan speeds or complete failure of the blower motor.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

What are the initial diagnostic steps to take when the heater isn't working in a 2020 Mercedes-Benz S65 AMG?

When faced with a heater malfunction in your 2020 Mercedes-Benz S65 AMG, start by checking the thermostat to ensure it is set correctly and functioning as intended, as a faulty thermostat can significantly impact heating performance. Next, inspect the coolant level in the radiator; low coolant can lead to inadequate heating, so topping it off may resolve the issue. If the coolant level is sufficient, examine the heater core for any signs of clogs or leaks, as these can obstruct the flow of hot coolant. Additionally, assess the heater blower motor to confirm it is operational, since a malfunctioning blower can prevent warm air from circulating into the cabin. Finally, review the HVAC controls to ensure they are working properly, as issues with the control panel or wiring can also affect heater functionality. By systematically following these steps, you can effectively diagnose and address the heating issue in your vehicle.

What are the common problems that could cause the heater to stop working in a 2020 Mercedes-Benz S65 AMG?

When troubleshooting a heater that has stopped working in a 2020 Mercedes-Benz S65 AMG, it's important to consider several common problems that could be at play. One of the first things to check is the thermostat, as a faulty unit can prevent warm air from circulating effectively. Additionally, ensure that the coolant level is adequate; low coolant can significantly hinder the heating system's performance. Another critical component to inspect is the heater core, which can suffer from clogs or leaks, leading to insufficient heat in the cabin. Don't overlook the blower motor either, as a malfunction here can disrupt the flow of warm air through the vents. Lastly, electrical issues, such as blown fuses or damaged wiring, can also impede the heater's operation. By systematically examining these areas, DIYers can identify and address the root cause of the heating problem, ensuring a comfortable driving experience.

How urgent is it to address the non-functioning heater in a 2020 Mercedes-Benz S65 AMG?

When faced with a non-functioning heater in your 2020 Mercedes-Benz S65 AMG, the urgency to address the problem cannot be overstated. A malfunctioning heater not only compromises your comfort during cold weather but also poses significant safety risks. Without a working heater, defrosting your windows becomes a challenge, which can severely impair visibility and increase the likelihood of accidents. Moreover, delaying repairs can lead to more extensive damage within the heating system, resulting in costly repairs that could have been avoided with timely intervention. For DIY enthusiasts, it’s crucial to recognize that while some issues may seem minor, they can escalate quickly if not addressed. Therefore, taking immediate action to diagnose and repair the heater will not only enhance your driving experience but also safeguard your vehicle's overall health and performance.

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2020 Mercedes-Benz S65 AMG Heater Issues & Repair Guide