What does the blower relay do?
In a blower motor, the relay supplies the power that allows the fans to circulate warmed air. Essentially an on/off switch, the blower motor relay’s reactions start and end the heating process in HVAC systems by controlling the flow of current between the power source and the motor.
How do you diagnose a bad blower motor resistor?
What are the symptoms of a bad blower motor resistor?
- No Air.
- High speeds only.
- Low speed only.
- Fan won’t turn off.
- Blower motor works on some settings but not others.
- Smoking vents.
- Burning smell.
What causes a bad or failing blower motor relay?
Blown fuses. One of the first symptoms of a bad or failing AC blower motor relay is a blown AC blower motor relay circuit fuse. 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…
Why is my heater blower motor resistor not working?
This occurs due to the failed blower motor resistor not being able to control the flow of electric current, it could be that the resistor is somehow bypassed and the power is directly being fed from the switch. Excessive current can overheat and permanently damage the blower motor resistor
What should I do if my blower motor is not working?
If it’s good, refer to a wiring diagram for your vehicle and conduct these tests: Disconnect the electrical connector at the blower motor and jumper power and ground to the motor, bypassing all the speeds controls.
What causes a blower motor to overheat?
Decreased airflow causes the blower motor resistor to overheat and fail. Reduced airflow also causes the blower motor to work harder, draw more current and that can cause repeat blower motor resistor failures. Blower motor is drawing too much power. Check the cabin air filter for clogging.
Blown fuses. One of the first symptoms of a bad or failing AC blower motor relay is a blown AC blower motor relay circuit fuse. 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…
This occurs due to the failed blower motor resistor not being able to control the flow of electric current, it could be that the resistor is somehow bypassed and the power is directly being fed from the switch. Excessive current can overheat and permanently damage the blower motor resistor
Why is my blower not working on my GMC Sierra?
When you switch to high,the blower motor relay coil circuit is grounded and voltage is now applied directly through the relay to the blower motor; bypassing the resistors. So, I would look to see if the relay is ok. It is a five terminal relay.
Why is my blower not working in Hi ( 5 )?
The usual failure of the resistor pack is if it works in HI (5) but not in any other mode or just a few modes. When you switch to high,the blower motor relay coil circuit is grounded and voltage is now applied directly through the relay to the blower motor; bypassing the resistors. So, I would look to see if the relay is ok.
