What is the Blower Motor Relay all about?

Most of your car’s accessories require a relay in order to operate – your headlights, the cooling fan on the radiator, etc. This includes the blower motor that pushes conditioned air out of the vents and into the cabin of the car. Your vehicle will have at least one blower motor relay. If you have more than one blower motor in the vehicle, such as with a rear air conditioning system, each separate system will have its own relay in place.

Think of the relay like a controller – it determines whether the system operates or not when you turn the switch. If the blower motor relay fails, you’ll have no fan functionality in most instances, although some systems provide control of the “high” fan setting to the fan switch itself, rather than the relay (note that this varies considerably from one vehicle to another).

Over time and through normal use, the blower motor relay may degrade and fail. When it does, you’ll need to replace it in order to enjoy proper airflow in the car.

Keep in mind:

• The blower motor relay is not inspected during any maintenance service.
• The blower motor relay is generally located in the under-hood fuse box or in the under-dash fuse box.
• A blown fuse can mimic relay failure.
• A failed blower motor switch can also give many of the same symptoms.

How it's done:

• The Blower Motor Relay is verified that it needs to be replaced. The blower motor relay is located by the blower motor or in the relay panel.
• The defective Blower Motor Relay is disconnected or the relay is pulled out of the socket.
• The socket or connection is checked for damage. If there is no damage the new Blower Motor Relay is installed.
• The Blower Motor Relay is tested for operation by turning on the blower.
• The vehicle is tested to ensure proper operation of the Blower Motor Relay by running the blower at all speeds.

Our recommendation:

It is essential that you have an operational blower motor as it makes driving more comfortable and enables you to keep foggy windows clear. Over time, the relay can degrade. If your blower motor isn’t functioning correctly, have the problem diagnosed by one of our expert mechanics and replace the blower motor relay if necessary.

What common symptoms indicate you may need to replace the Blower Motor Relay?

• Blower motor does not work on high speed
• Fan does not work at all

How important is this service?

While your air conditioner and heater are technically accessories and not critical to vehicle operation, they are important. If you’re experiencing any problem with the blower motor, have it diagnosed and repaired by one of our expert mechanics.