Where is the blower motor in a Mercedes Benz?
The blower motor controls air flow into the passenger cabin in conjunction with the blower motor resistor (final stage). It is mounted in the heater housing behind the right side of the dashboard. The blower motor speed is adjusted via the HVAC control panel through the blower motor final stage.
Why does my air conditioner blower make a whining sound?
The blower motor and resistor move the air through the HVAC system. If you are starting to hear a whining sound when the motor is running or the motor doesn’t run at all there is a good chance that the motor is going bad.
Why are my blower motor resistor connectors not working?
Blower Motor Resistor Connectors. When your air conditioning or heat stops blowing air, one of the leading causes is a failure of the blower motor resistor. Many times the root cause of the failure is a melted blower motor resistor connector or pigtail.
How to tell if blower motor is failing?
If you suspect your final stage is failing, look for the following symptoms: Blower motor speed fluctuates from high to low. Blower motor does not turn ON. Blower motor only runs at one speed. Over time, a blower motor may become noisy as the motor electrical contacts wear.
Where is the regulator on a Mercedes fan blower?
The Mercedes Benz fan blower motor regulator is a series of resisters in a printed circuit board about 2-inches square located right next to the blower motor.
Where is the resister on a Mercedes Benz fan?
Just to the left of the blower motor, an electrical connector connected to a flat 1-inch-by-2-inch plate can be seen. This is the blower motor resister, which controls the fan speeds. Disconnect the multi-wire connector from the blower motor resister next to the blower motor. Start the car and turn the air conditioning on.
What happens when the blower motor does not come on?
As a note, 85 percent of the time when the blower motor does not come on or operates at one speed only, the blower motor resister is at fault. The resister emits substantial heat from the resistance it supplies and eventually burns up. The resister is inexpensive as parts go and is simple to replace.
How much does a blower motor regulator cost?
The cost is $640 (R4800) from MB dealer. From a second hand dealer it is $120 for just the regulator that fits the newer blower. I decided that it was too risky, firstly to spend so much on a regulator and blower to which has already failed three times in the past 8 years.
With the tab pulled down turn the motor clockwise and wiggle and pull it down and out of the housing. With the motor out of the vehicle you can better see the tab you will be gently pulling down on (red arrow). The housing goes up to the air box in the engine compartment (red arrow).
What are the symptoms of a bad blower motor resistor?
Another common symptom of a faulty blower motor resistor is a a blower motor that does not function on certain settings. If the blower motor resistors’ internal components fail it may cause the blower motor to malfunction, or not function at all on one or more of the settings.
Why is my blower motor stuck on one speed?
Blower motor stuck on one speed A common symptom of a faulty blower motor resistor is a blower motor that is stuck on one setting. The blower motor resistor is the component directly responsible for controlling the blower motor fan speed. If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed.
How many volts does a blower motor have?
Your DVOM should read battery volts (green arrow). If the blower motor is running, it will be about 12 volts with a vehicle power supply on. If just testing using your battery, expect a two-volt drop from what open circuit battery voltage is at the time.
The blower motor controls air flow into the passenger cabin in conjunction with the blower motor resistor (final stage). It is mounted in the heater housing behind the right side of the dashboard. The blower motor speed is adjusted via the HVAC control panel through the blower motor final stage.
If you suspect your final stage is failing, look for the following symptoms: Blower motor speed fluctuates from high to low. Blower motor does not turn ON. Blower motor only runs at one speed. Over time, a blower motor may become noisy as the motor electrical contacts wear.
Your DVOM should read battery volts (green arrow). If the blower motor is running, it will be about 12 volts with a vehicle power supply on. If just testing using your battery, expect a two-volt drop from what open circuit battery voltage is at the time.
What to do if your Mercedes Benz fan is stuck?
Not hard to do, just drop the blower motor and replace the regulator. The hardest part is positioning your self under the dash and looking upwards to locate the mounting screws. Hi Paul, just wondering if you found a solution to your stuck fan.
What causes the a / C blower to run uncontrolled?
Mostly (according to this forum) a failed BR causes the a/c blower to run uncontrolled. Btw your WIS a/c circuit diagram is not identical to mine for W208. However the blower motor/regulator part is the same. Still the Regulator?
Why does my blower motor not turn on?
Blower motor does not turn ON. Blower motor only runs at one speed. Over time, a blower motor may become noisy as the motor electrical contacts wear. I have also seen debris from a rodent get trapped in the blower cage creating a vibration or noise. If your blower is noisy, pull it down and see if there is something stuck in it.
What causes a blower motor to stop working?
In a situation where the motor doesn’t work on any speed, the most likely causes are: a blown power supply fuse, a bad motor ground connection, bad motor speed control module or a failed motor. On all systems, a failed blower motor is least likely. Blower motors generally don’t fail out of the clear blue.
Just to the left of the blower motor, an electrical connector connected to a flat 1-inch-by-2-inch plate can be seen. This is the blower motor resister, which controls the fan speeds. Disconnect the multi-wire connector from the blower motor resister next to the blower motor. Start the car and turn the air conditioning on.
What kind of motor does a variable speed blower use?
Variable speed blower motors don’t use a blower motor resistor. Instead they use a blower motor speed control or a power transistor. Variable speed motors are most often used in vehicles with automatic climate control.
How is the blower motor on a Mercedes 140?
The blower motor on a 140 is controlled by the NEGATIVE pole. I understand that a lot of cars use this same technique. So the closer the negative on the motor is to a short circuit (0 volts), the faster the motor runs. Keep that in mind.
What happens if you have a bad blower motor?
The blower motor is the component responsible for pushing air through the vents of your vehicle’s heating and air conditioning systems. Without it, the AC system will not be able to circulate any heated or cooled air.
Why is my W140’S class blower not working?
The symptoms are similar to low fan rpm, just restricted airflow. This fan is the original in my 98 S500. Notice the corrosion here and there – and I removed it to clean it up about a year ago. The motor bolts and the aluminum case itself seem to be subject to corrosion.
What causes a fuse to blow on a blower motor?
If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may cause the blower motor fuse to blow. Any sort of electrical spikes or excessive current from a bad relay will blow the fuse and cut power in order to protect the system.