Quick Answer: How do you tell if it’s the blower motor or resistor is bad?

Problems with a blower motor resistor are common in many cars. The most common symptom of a failed blower motor resistor is when the heater fan only runs at the highest speed setting (4 or 5) and doesn’t work at low speeds. In some cars, a failed blower motor resistor can cause a heater fan to stop working completely.

How do I know if I need a blower motor or a resistor?

Blower Motor Resistor Test

Typically, if the fan will work on some speeds but not on others, the resistor is suspect. Okay, let’s say there’s no melting going on, but your fan doesn’t work on all speeds. Typically, if the fan will work on some speeds but not on others, the resistor is suspect.

What are the symptoms of a bad blower motor?

What Are Signs Your Blower Motor Needs to Be Replaced?

  • Poor or Airflow from Air Vents. This will be the first and most obvious sign your blower motor has a problem. …
  • No Airflow At All From Vents. …
  • Skyrocketing Energy Bills. …
  • Strange Noises When You Turn on the Heat. …
  • Overheating Blower / Weird Smells.
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Should I replace blower motor and resistor?

We do suggest that you replace the resistor at the same time. It may not be critical, but this will keep the system more uniform. The issue may even be related to the resistor. If you know that it is not related to the issue, then you do not have to replace it.

What happens when your blower motor goes out?

No air from the vents

If the heater blower motor burns out or short circuits, it will not function, and therefore will not be able to produce any airflow for the system. The blower motor will usually have to be replaced in order to restore proper operation to the system.

What happens when a blower motor resistor goes bad?

Blower motor resistor / control module problems

The most common symptom of a failed blower motor resistor is when the heater fan only runs at the highest speed setting (4 or 5) and doesn’t work at low speeds. In some cars, a failed blower motor resistor can cause a heater fan to stop working completely.

What happens when blower motor relay goes bad?

If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may cause the blower motor fuse to blow. Any sort of electrical spikes or excessive current from a bad relay will blow the fuse and cut power in order to protect the system.

How much is a motor blower resistor?

Car Blower Motor Resistors – Sold Individually, Kit from $12 | CarParts.com.

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Why will a blower run on the on position and not on auto?

Other Blower Fan Won’t Run Problems

The fan will run and blow warm air but only in FAN or FAN ON mode – delivering heat – but NOT in AUTO mode. This is a bad temperature sensor in the unit; replace the fan limit controller.

Why is my blower not working in my car?

If little air is coming through the vents (hot or cold), then it could be because the blower motor for the fan or a switch or resistor that controls fan speed isn’t working. Another cause might be that the electronically controlled “blend doors” that direct air flow are stuck or broken.