Mercedes w163 A/C heater control Flap Actuator Motor

ML320 ML430 Blowing Hot Air Only Problem W163- SOLUTION

Is your ML blowing hot air even though you have the AC in a cold setting? A common problem with the ML320 / ML430 is the AC getting stuck on a Hot or Cold setting. This is caused by the blend motor flap getting stuck and no longer moving when you rotate the AC knob between Hot and Cold. If you remove the glove box, you can manually switch the blend motor flap. By manually moving the blender motor flap, you may be able to get it unstuck, and your AC could start to operate normally again. Otherwise, you need to replace the following part. Click on the link below to check the price on Amazon.

Defective Part

Mercedes w163 A/C heater control Flap Actuator Motor ml-class heating airflow

Part Number:
1638200108
163 820 01 08

A common symptom of this part failing is the fact that only hot air blows from the vents. The air coming in may be cold, your AC setting is on cold but you get only hot air from the vents.

How to check the A/C air blend motor flap

The following video will show you how to check the operation of the A/C air blend heater flap. You can also manually switch the stuck flap to COLD settings if you need a temporary solution. Overwise buy the part above and replace it.

Solution

Start by removing the glove box. Open the glove box and you will see the four screws that hold it in place.
Once you remove the screws pull out the glove box.
Behind the glove box (on the left) you will see a white plastic arm. This is the flap that switches the airflow from hot to cold. It gets stuck in the HOT position. After you remove the glove box put your hand through and manually move the flap a couple of times. If you want to switch it to cold you need to push the flap (white arm) toward the front of the car.
You can turn the AC to hot and cold a couple of times. Pay attention to the white arm on top of the blender motor.
Mercedes w163 A/C heater control Flap Actuator Blend Motor

Replacing the blend motor

First, try to operate it manually a couple of times. Hopefully, it will start to work again. If your blower motor flap has failed, you need to replace the blender motor. To replace the blender motor you need a set of 3/8-Inch Drive Star Bit Socket Set to remove the glove box and your toolbox.