Quick Answer: Why does my blower motor only work on low speed?

When a blower resistor fails, the highest fan speed usually is the only one that still works because it essentially bypasses the resistor and receives the maximum amount of voltage. When the resistor is working, it reduces the amount of voltage going to the lower fan speeds so the fan runs slower.

Why does my blower motor not work on high?

In a situation where the motor doesn’t work on any speed, the most likely causes are: a blown power supply fuse, a bad motor ground connection, bad motor speed control module or a failed motor. On all systems, a failed blower motor is least likely.

What are the signs of a bad blower motor resistor?

Usually a bad or failing blower motor resistor will produce a few symptoms that can alert the driver of a potential issue.

  • Blower motor stuck on one speed. …
  • Blower motor does not work on certain settings. …
  • No air from the vehicle’s vents.

How is a blower motor speed controlled?

The blower motor resistor is responsible for controlling the blower motor speed. … Each fan speed selection is connected to one or more of the resistors in the blower resistor assembly. The change in resistance controls the current through the blower motor, which in turn limits the speed that the blower motor spins at.

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Why does my blower motor only work on high?

Most car manufacturers use a series of resistors to make the heater blower motor run at different speeds. And when one or more of these resistors burn out, you’re usually left with only one heater blower motor speed—high. The resistor module is easy and inexpensive to replace.

Where is the blower resistor located?

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 do you check a blower motor resistor?

Place one lead of the Ohmmeter on terminal 1 of the resistor. Place the other lead on terminal 2 and check against specifications. If this circuit is open, showing infinity on the Ohmmeter, the blower resistor must be replaced. Move the lead from terminal 2 to terminal 3 and check this reading against specifications.

How can I make my blower motor faster?

You can increase or decrease the blower speed by slightly adjusting the pulley on the blower drive motor. To increase blower speed, slightly loosen the setscrew that holds the pulley to the driveshaft. Move or turn the pulley clockwise on the shaft one turn, then tighten setscrew.

How do I adjust the blower speed on my furnace?

When increasing the blower speed, loosen the setscrew a little bit. This is the part that holds the pulley to the furnace’s driveshaft. Turn the pulley one rotation clockwise on the shaft. If you want even more speed, do two rotations.

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How much is it to replace a blower resistor?

The average cost to replace the blower motor resistor at a repair shop is between $44 and $55 in parts and $70 in labor costs, for a total cost of around $114 to $125.

What is the primary cause of a blower motor that only operates on its highest speed?

A bad blower motor resistor can cause your blower works on high speed only. Older style blower motor resistor with exposed resistor elements. The blower motor resistor is what’s responsible for giving you three blower speeds. The resistor block contains three different high resistance coils.