Mercedes S-Class W220 DIY A/C Recharge Instruction

If the Air Conditioner on your 2000-2006 Mercedes-Benz S-Class W220 is not working, you can try to refill the system with the R134a refrigerant. If the refrigerant level in the system gets too low, which is a common problem in older cars, the Air Conditioner Control Unit shuts off the A/C to protect it from getting damaged. In many cases refilling your car with refrigerant will fix A/C blowing hot air problem. 

Parts Required

• Recommended R134 A/C refrigerant refill/aircon refill / A/C Refill

Here are a few A/C refrigerant refill kits that are highly ranked and affordable. If you are interested in any of them, links have been provided for you to read reviews and check current prices on Amazon.

	A/C PRO ACP-100 Professional Formula R-134a Ultra Synthetic Air Conditioning Refrigerant Reusable dispenser and gauge Temperature adjustment gauge Larger than other aircon kits – 20 oz
	Interdynamics MAC-134 EZ Chill Refrigerant Refill Charging Gauge Added oil Leak Sealer Size – 18 oz
	3 Cans R-134a DuPont Suva A/C Automotive Refrigerant/Freon R134a Just R134a refrigerant nothing else Meets AHRI-700 and SAE J2776 Purity Standards By Dupont the R-134a inventors Great Price

 

How to charge the A/C in your Mercedes-Benz S-Class W220

This video shows how to recharge the air conditioner on your Mercedes-Benz. Charging the system with a refrigerant charging kit can take between 5 to 10 minutes depending on the system’s capacity.

Before we begin, remember: These instructions may vary depending on the AC recharge kit that you are using. Be sure to always read the instruction notes on your R134a refrigerant kit. The gauge that you will see in our video is similar to the gauge found on onebest-sellingling A/C recharge kits, the A/C PRO ACP-100.

 

1. Turn the engine on and let it idle. Turn the air conditioner ON and set it to the maximum cooling setting.
2. Open the hood of your S-Class and locate the low-pressure AC service port and remove the cap.
   
3. Attach the refrigerant gauge to the service port. You will need to press and hold the quick-release at the end of the hose, insert it into the AC charging port then release it.
4. Rotate the dial on the lens until the red arrow in the middle of the V is pointing to the temperature corresponding with the outside temperature. If the pressure is below the range of the V and the air climate control is blowing hot air that means the system is low on refrigerant and you can proceed with charging the system.
5. Read the pressure in your air conditioner system. If the pressure is low the gauge reading will be in the white zone. If the pressure is normal then the gauge should be in the green zone. You should not have a reading on the HIGH / RED zone except when the car is turned off, in which case it is normal.
6. Always keep the can UPRIGHT. As you charge the system shake the can slightly every two or three seconds while you are charging.
7. Every 30 seconds release the trigger to stop the charging process and read the pressure. Be careful to not overcharge the system. On our gauge overcharging was marked in red. Note that the system may show overcharged with the engine turned off and that is normal.
8. Stop recharging the system when the pressure needle is within the V range in the green zone. 
9. Detach the connector from the low-pressure AC port. Reinstall the cap, close the hood, and enjoy your A/C system again.

IMPORTANT NOTES

• DO NOT TURN THE CAN UPSIDE DOWN WHILE CHARGING. Only gas should go into the AC system. If you turn the can upside down the AC system will get liquid refrigerant which can cause the AC compressor to lock up and also wash out the oil. Keep the AC refrigerant can in the up position and only shake it slightly while charging.
• If the refrigerant level is very low, the AC compressor will not engage. Charge the AC system for a couple of minutes with the engine running, and you should notice the AC compressor engages/kick in once you add enough refrigerant into the system.
• Once the A/C kicks in and the air conditioning system starts to work the pressure on the system may drop. Continue to add freon until the system shows pressure on the correct range correlating to the outside temperature.

W220 S-Class A/C Hidden Menu

Like in other Mercedes-Benz models climate control can be used to troubleshoot the A/C system. In order to troubleshoot your S-Class via the climate control display, you need to enter the secret/hidden aircon diagnostic menu. If you want to learn how to do that read this article: How to access A/C Hidden Menu on W220.

Mercedes-Benz A/C doesn’t work after a recharge?

If you used a recharge kit to top off your A/C system but the air conditioner still doesn’t blow cold air then it may be time to take your car to an auto repair shop for an A/C diagnosis. A professional needs to perform a dye test and check the system for leaks.

Mercedes-Benz Air Conditioning Service Cost

A Mercedes-Benz specialized shop may charge you between $100-$150 to diagnose your A/C system.

Important factors to keep in mind when charging the A/C system are:

• Ensure the system is sealed and not leaking.
• Ensure the system does not have any moisture or air in it. An A/C vacuum pump is needed to achieving this.
• Ensure the compressor is operating correctly. Including the serpentine belt. Make sure the cooling fans work.
• Clean out the condenser by the radiator! Dirt and leaves build up in there over the years. Take a garden hose and clean it.
• Add the correct refrigerant amount. Don’t guess! There is a label under the hood that tells you how much to add.
• Do not introduce liquid R-134a into the system. Only gas should enter via the A/C low-pressure charging port.

AC Light Flashing on my Mercedes-Benz

If the A/C light is flashing on the Climate Control it means that there is a fault code on the Aircon Control Unit. In order to find out what the problem is, you will need a diagnostic scanner that can read fault codes.

The YOUCANIC full system diagnostic scanner is an essential tool for troubleshooting Mercedes-Benz problems. This powerful diagnostic tool can help identify and diagnose issues with your vehicle’s engine, transmission, brakes, and other critical systems by reading and interpreting fault codes stored in your car’s computer system. With detailed information about the problem at hand, you can make more informed decisions about repairs and maintenance, potentially saving time and money on costly repairs.

In addition to its diagnostic capabilities, the YOUCANIC scanner can also perform diagnostic tests on various systems, including the ABS, airbag, and steering systems, to help pinpoint the root cause of any issues. Whether you’re a DIY mechanic or a professional technician, this tool can help you diagnose and solve even the most complex automotive problems with ease, making it an essential tool for anyone who wants to maintain their Mercedes-Benz and keep it running smoothly for years to come. With the YOUCANIC scanner in your toolbox, you can approach any Mercedes-Benz problem with confidence, knowing that you have the tools and knowledge to tackle any issue that arises.

When you attach the gauge, the pressure is in the red zone.

This may happen because the engine is off or the A/C compressor is not engaged. It is normal for the pressure to be high when the engine is turned off. It should not be high when the compressor is engaged.

You measure the aircon gas pressure and the gauge shows zero.

This could happen because the system is very low on refrigerant. It could be that the system has a major leak. An auto repair mechanic will have to perform a dye leak test to find the A/C problem.