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Cooling

Temperature Management

Nowadays, most cars are equipped with climate control

 

which has imposed greater demands on temperature management inside the car. Valeo, a key supplier at OEM level, is supplying all of its know-how to the aftermarket.

Let’s start with the basics to understand what the blower motor function is and the constraints that exist.

On any vehicle with a heater or air conditioning system there will be a heater blower motor or an air conditioning (A/C) blower motor to force air across either an evaporator or a heater core.

The heater blower motor works to maintain a constant flow of air from outside to inside the cabin and also ensures air circulation within the cabin if the recycling function is switched on.

The blower motor is located in the Heater Ventilation Air Conditioner (HVAC) module between the cabin air filter and the evaporator or heater core and is designed specifically to optimise the heater and air conditioning. Due to its purpose, it will be in contact with outside air, which means it may be subject to extreme temperature variations and dirt ingress unless the car is equipped with an effective cabin air filter.

The blower is a key component in ensuring the occupants comfort in the vehicle. I t has to meet the requirements of the OE product equipment to be able to supply to the occupants of the cabin a sufficient air stream and an optimal distribution of air.

Technology used

There are two types of blower:

– Helicoidal: Technology used in older cars, it has a simple design but has a high noise level

– Centrifugal: Technology adapted to higher pressures, it has a lower noise level and is very popular on recent applications

Blower motors are controlled by a variable resistor to regulate the motor’s speed. When a higher fan speed is selected the resistor allows a higher current though to the blower motor allowing it to spin faster, thus moving more air into the cabin.

Causes of Blower Motor failure

Due to its location, over a period of time, issues can develop with the air blower:

– Increased noise caused by debris in the air ducts (if there is an ineffective cabin air filter in place)

– Engine axis misalignment

– Faulty speed regulators (automatic A/C)

– Faulty electric motor

– Rust caused by a coolant leak

The blower must be replaced if it is not performing, as the driver will not be able to use the heater or air conditioning. This will also result in reduced visibility as no demist function will be available, which is critical to safety.

A good indicator of a faulty blower motor can be a tripped fuse. This is caused by dirt ingress on the motor which prevents it from rotating.

If there is no air flow regardless of the position of which the blower switch is set, the blower motor cycle can be checked by connecting the motor directly to the battery. If it still functions and the fuse is intact then the blower motor resistor may need replacement.

Repair advice

On the same vehicle application, the blower motor can be different dependent on the following: – Car with manual or automatic air conditioning – Right hand drive and left hand drive to access and replace the blower motor, some removal of the dashboard and interior trim is often necessary.

Before installing, the direction of the rotation should be checked; in addition to making sure the axis of the blower is well aligned.

Choose OE Quality parts

Fitting OE quality blowers ensures optimum performance of the A/C system and provides the following: – Correct dimensions for an easy fit – Avoidance of corrosion for longer performance – Minimal noise level to improve comfort – Accurate power level for optimum air flow

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