How can you tell if your heater blower motor resistor needs to be replaced?
If you are experiencing problems with your HVAC blower motor, it doesn't always mean that it's gone bad. There are several mechanical and electrical components (the fan blade, motor, and resistor just to name a few) all working in unison to bring you the hot or cold air you want. What are the signs of a bad blower motor resistor? There are actually three most common indications that it is failing, and they all have to deal with the amount of air flowing out of the vents. First, if you notice no air flow on the lower fan setting, your heater blower resistor may not be working properly. It is preventing the circuit from closing between the contacts when the current is at its lowest. Second, you may also notice that the blower isn't working unless your car is running at higher RPM. This is a byproduct of the same issue, and unless there is enough current to make the leap between contacts then the blower will run intermittently. Third, and most difficult to diagnose, is a certain amount of reduced air flow all around. With a damaged HVAC blower motor resistor, it is possible that not enough current is reaching the load and the blower won't turn as hard. This may be an indicator of a bad motor as well, so further testing with an ohmmeter is recommended.
What does the blower motor resistor do?
Blower motor resistors work the same way other resistors do. They restrict current running through a circuit and deliver a lower amount of amperage to a load. Since the device it controls is a HVAC blower motor and it functions on variable levels of speed, the blower resistor (pack) must also function on variable levels. On "high", the full amount of amps are allowed to reach the fan and run it at full speed. Each step down will increase resistance and slow the blower motor. Heater blower resistors don't look like a common in-line resistor. They usually have a wire harness connector on one side of the mounting flange, and some sort of heat sync or resistor coil on the other. These components absorb heat and will eventually break.
Usually, it's an easy job.
When it comes time to replace your blower motor resistor, it usually isn't that difficult. On most vehicles, you can find it right next to your blower motor and can access it behind your glove box. If you run into any difficulty, your owner's manual will usually help. Once you have located your blower motor resistor, you should first unplug the wire harness connector. Then, unscrew it from the mounting flange. Your new resistor can be installed in its place - simple.
The right parts, guaranteed.
All modern cars and trucks today have variable speed climate control systems. Essential to this function is the HVAC blower motor resistor's ability to regulate the amount of current reaching the blower. Because it is an electronic device that is under constant strain and stress, the overheating can take its toll over the years. That is why it's important to purchase a quality replacement blower motor resistor when you need one. At Car Parts Discount, we carry original equipment as well as new aftermarket resistors for almost all applications. That means that if you are in the market for a blower motor resistor for your car, we can supply it right away at a price that anyone can afford.