Where is the resistor on a blower motor?

Because resistance creates heat while current is flowing, the blower resistor is mounted in the duct near the blower motor so the resulting airflow will keep the resistor cool.

How is the resistance measured on a heater blower?

If the appearance is normal, it is necessary to a degree the resistance throughout every individual resistor. The resistors are all linked to a single common point. Switch the multimeter to the resistance measuring mode, connect one probe of the multimeter to the commonplace point and use the other probe to degree resistances at other points.

Where is the blower motor in a HVAC unit?

The blower motor is a fan housed in the heating, ventilation and air conditioning (HVAC) ducts, normally located behind the glove box. It uses a resistor to change the speed at which the fan operates.

Why does heater blower motor increase in resistance?

As part of our comfort and luxury, the blower speed is one of the most adjusted settings in a car, and so the resistance of the blower motor is constantly being put under stress, which can eventually lead to motor failure; too much humidity in the atmosphere can lead to an increase in resistance.

What happens if you overheat the blower motor resistor?

Excessive current can overheat the blower motor resistor and permanently damage it. In this case, the heating and air conditioning system might still function normally by pushing the cold or warm air out of the outlet alongside the speed. The resistor must be replaced with a new one to restore its function. 3. Blower motor only working on low speed

Where is the blower motor resistor located on a car?

It’s located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.

How to test Honda Accord blower motor resistor?

Testing Honda power transistor (blower motor control module). For example, in the 2009 Honda Accord, the service manual describes the procedure as follows: Turn the ignition to ON. Press and hold the OFF button and within 10 seconds press and release the Window Defogger button five times.

What are the symptoms of a bad heater motor resistor?

Symptoms of a Bad or Failing Heater Blower Motor Resistor. 1 1. 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 2 2. Blower motor does not work on certain settings. 3 3. No air from the vehicle’s vents.

How to test a Mercedes Benz fan blower motor regulator?

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. Test the connector for power at the terminals in the connector using the voltmeter. If there is power, reinstall the connector to the resister.

Can a broken motor switch stop a blower?

A broken blower motor switch can also stop the blower from changing to certain speed settings. If your blower motor cannot change to certain speeds, check both the resistor and the switch on your dashboard. The most common failure points are the resistor and the motor itself.

What are the resistors on a blower motor?

The purpose of these resistors is to reduce the amount of the blower motor’s current that’s passing through them. As you select a blower speed, the blower motor switch reroutes battery power to a specific combination of one, two or all three of these resistors (within the blower motor resistor assembly).

Where is the blower resistor on a 1988 Chevy?

The blower motor resistor (located on top of the heater core housing and behind the glove box) isn’t hard to test. In this tutorial I’ll show you how to continuity test it with a multimeter in Ohms mode ( Ω ). NOTE: This tutorial only applies to the 1988 to 1993 vehicles listed in the ‘Applies To:’ box on the right column.

What kind of blower resistor do GMC pickups use?

NOTE: This tutorial only applies to the 1988 to 1993 vehicles listed in the ‘Applies To:’ box on the right column. Some 1994 Chevy/GMC pickups use this type of blower resistor. For the 1995 and newer blower resistor test, the following tutorial will help:

How is the speed of the blower motor controlled?

On climate control systems without automatic temperature controls, the blower motor speeds are controlled by a switch wired to a stepped resistor that usually includes a thermal fuse.

How does a relay work on a blower motor?

Finally, with the fan switch on the highest speed, the fan motor is receiving system voltage (14.5 with the engine running). Some systems will energize a relay when the switch is set at the highest fan speed. The relay then closes its contacts, feeding full voltage to the fan, because a relay can handle the current better than the fan switch.

Because resistance creates heat while current is flowing, the blower resistor is mounted in the duct near the blower motor so the resulting airflow will keep the resistor cool.

On climate control systems without automatic temperature controls, the blower motor speeds are controlled by a switch wired to a stepped resistor that usually includes a thermal fuse.

The blower resistor is located beyond the blower motor in the picture below. It has the seven wire, multicolored harness attached to it. In the next picture I show the connector that goes to the blower motor. It has a locking tab that has to be depressed with a small screwdriver or other device.

Where does the ground go on a blower motor?

The way this circuit works is all on the ground side. 12 volts is always present at the motor, and the switch in your dash provides the ground. On speeds 1-3 the ground is re-routed through the resistor pack and on high speed it bypasses the resistor pack and the motor gets full voltage.

What causes a blower motor to heat up?

Heat either caused by poor airflow across the resistor pack resulting in poor cooling, or heat caused by a higher amperage draw from a worn out motor with poor lubricated bearings/bushings or worn brushes. If the motor was serviceable, that would be the next route I would take.

How to test circuit coming in from low blower?

If you want to test the circuits coming in, it will be as follows: Terminal “A” Tan = Speed 2, power through blower switch from Low Blower fuse, 20 amp, Ignition Terminal “B” Yellow = Speed 1, power through blower switch from Low Blower fuse, 20 amp, Ignition

How can I tell if my blower motor resistor is faulty?

Another symptom of a faulty blower motor resistor is no air from the vehicle’s vents at all. Power to the blower motor is fed through the blower motor resistor, so if it fails or has any issues power can be cut off to the motor.

What does the blower motor resistor do in a car?

The blower motor resistor is an electrical component that is a part of the vehicle’s heating and air conditioning system. It is responsible for controlling the blower motor’s fan speed. When fan speed is changed via the knob on the instrument cluster, the blower motor resistor changes setting, which changes the speed of the blower motor.

How many ohms does a blower motor resistor need?

According to the service manual, it must be around 4-5 ohms. In our case the ohmmeter shows open circuit, which means the resistor has failed. Sometimes, a blower motor resistor might fail due to problems with the blower motor itself.

What causes a blower motor to not work?

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. This can also be caused by a blower motor switch, so a proper diagnosis is highly recommended if you are uncertain of what the issue may be.

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