Failed fan resistor - what are the symptoms?

Under the impression that the airflow in your car is not working properly? The glass smokes intensely, and you feel less and less confident behind the wheel? The cause may be a damaged fan resistor, which gives very similar symptoms. However, the first diagnosis is not always correct, and the reason may be different. So how do you recognize a defect in a resistor and should you always replace it with a new one?

What will you learn from this post?

• What is a blower resistor and what function does it have in a car?
• What are the symptoms of a damaged resistor?
• What component failures have similar symptoms?
• Can a damaged fan resistor be repaired?

Shortly speaking

The blower resistor is the part of the car's electrical system that determines the power of the blower. If it is damaged, it may be difficult to control the strength of the airflow. However, the failure of the resistor has symptoms similar to the failure of other components of the ventilation system. In this case, it is important to quickly and accurately diagnose and determine the source of problems.

Supercharger resistor - what is it and what is it responsible for?

Blower resistor (also called heater blower resistor) element of the electrical system with which the fan motor can be controlled. With the appropriate switch, slider or knob, we activate the corresponding resistor circuit and thus control the blowing power in the vehicle. If one or more resistor circuits fail, you will experience a fairly common ailment - the blower will not operate at full speed range.

Actually, it's a failure. A damaged blower resistor gives quite specific, but at the same time "insidious" symptoms. So it's worth knowing how to approach car diagnostics.

The most common symptoms of a fan resistor failure

Although we first touched on the symptoms of a defective blower resistor, it is worth dwelling on this issue a little longer. The two most common symptoms of damage to this component are:

• Airflow control problem – it speaks for itself. There may be situations where controlling the airflow rate becomes very difficult or even impossible. For example, on a 4-stage airflow control panel, the 1st, 2nd and 3rd stage airflow will suddenly stop being activated. Interestingly though, the vent in gear 4 will work flawlessly and with the right amount of force for this setting. If you see something like this on your car, then with a high degree of probability you can assume that the main culprit is the supercharger resistor.
• Complete absence of air flow from ventilation - here, in turn, a situation arises when all ventilation mechanisms stop working, and not just the first three.

While the first scenario is fairly straightforward and prioritizes a faulty fan resistor as a possible source of problems, the situation gets more complicated if all ventilation ducts fail. The suspect list would then include the rest of the system, including: relay, fuse, or clogged air intake. Therefore, the identification of the real culprit should be entrusted to professionals.

If the resistor is good, what?

A professional mechanic will carry out diagnostics according to a predetermined scheme - He will start by checking the elements and assemblies that are the least hassle to repair or replace. (blower resistor, fuse), and then gradually move on to the most problematic. In case of difficulties with the regulation of the air flow, the cause of problems (in addition to the failure of the resistor) can also be:

• failure of the blower motor;
• Damage to the air control panel.

When the situation is more serious and the air supply stops completely, the problem may be:

• blown fuse (the simplest and cheapest malfunction to repair);
• damage to the relay (it is responsible for controlling a large current with a small current);
• Clogged air intake (clogged at least one air intake prevents air from entering the cab)
• damage to the ventilation duct (a malfunction of the air duct, for example, associated with its opening, makes ventilation in the cabin almost invisible);
• damage to the blower motor (it is responsible for pressing air into the passenger compartment).

Faulty fan resistor - repair or replace?

Repairing the fan resistor is not an option - it is a component that cannot be regenerated. If you notice the above symptoms in your car and are sure that they are related to a damaged resistor, you need to buy a new one. Luckily, you won't have to search long. Go to avtotachki.com and check out the offer of blowing resistors at the best prices on the market!

Also check:

Unpleasant smell from heating in the car - how to remove it?

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