Burnt yellow and brown wires at blower motor resistor, is this indicator of bad resistor or bad motor? 2011 Chevrolet Malibu
HVAC blower motor working intermittingly. when I inspected motor and resistor, I noticed the white and brown wires looked like they had gotten hot. There was some melting at the terminals coming off of the resistor where the brown on white motor wires plugged into the resistor. Is this an indication of a bad motor or bad resistor?
My car has 52000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi there – most likely, the problem is the blower motor resistor pack. A quick way to test this is if the blower fan still works in the "Max" position. If it does, that pretty-much rules out the motor as the problem. The resistor pack can get pretty hot while running the fan in lower settings, which could damage the wiring to it just from the heat. If the resistor shorts, increased electrical load could burn the wiring insulation as well. I would suggest an electrical inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.
How to Identify and Fix Common car Problems ?
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The blower motor resistor controls the power to the system`s blower motor. When it fails, it can cut off all power to the motor. When the blower motor doesn`t get power, air pressure can`t be produced. You are left with a heater or air conditioner with nothing coming out of the vents.
Odds are that some of the wiring in the motor/switch/resistor pack/wiring circuit got hot enough to melt the insulation so it is now shorting together somewhere.
If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed. The heating and air conditioning systems may still function at one speed, however the resistor will have to be replaced in order for full functionality to be restored.
One of the first symptoms of a problem with the blower motor relay is a blower motor that does not function. As the relay is the switch that supplies current to the blower motor, if it fails internally, then power may be cut off from the blower motor circuit causing the motor to no longer function.
A fuse is often located on the resistor board. The fuse only protects the low and medium blower speeds. High speed will still work if the resistor fuse is blown.
The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.
When electricity is conducted through a resistor, heat is generated and dissipated through the surrounding air. Under excessive voltage, a resistor generates so much heat that it cannot dissipate the heat quickly enough to prevent burning.
The blower motor that is drawing too many amperes will melt the resistor and wiring. Anytime the resistor is melted you should replace the blower along with the resistor and connections that show any heat damage.
The fan speed can be changed by switching the blower resistor resistance mechanically, using a rotating lever, or electronically by the air conditioning system. The blower motor resistor is responsible for controlling the blower motor speed.
Is the blower motor resistor supposed to get hot? Yes that resistor will get very hot. Most people don`t know this but it is faster to defrost the windshield on low or medium fan speed due to that resistor putting off heat.
Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.
How Many Ohms Should A Blower Motor Have? A good blower motor is expected to read over 0.5 Ohms.
The heating and air-conditioning system uses several resistors to supply the desired airflow by sending power to the blower motor.
The blower motor resistor is designed to last for the car`s lifespan. In most cases, these resistors will wear out long before the car does. Usually, the wear that the blower motor resistor has is due to the constant use that it gets and the heat that it is exposed on a regular basis.
The blower motor is drawing too much current, causing the lower resistors to heat up excessively, with the ultimate result of premature resistor failure and a possible fire hazard.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Burnt yellow and brown wires at blower motor resistor, is this indicator of bad resistor or bad motor? 2011 Chevrolet Malibu
ANSWER : Hi there – most likely, the problem is the blower motor resistor pack. A quick way to test this is if the blower fan still works in the "Max" position. If it does, that pretty-much rules out the motor as the problem. The resistor pack can get pretty hot while running the fan in lower settings, which could damage the wiring to it just from the heat. If the resistor shorts, increased electrical load could burn the wiring insulation as well. I would suggest an electrical inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.
How do I know if my blower motor or blower motor resistor is bad?
ANSWER : Hi Johnny. About 90% of the time, the problem is the resistor as opposed to the blower motor. A professional mechanic would complete an electrical test to determine if power is being sent through the resistor to determine which one is the issue. If you want to eliminate the guess work, you could have one of our mobile mechanics come to your location to complete an AC is not working inspection so they can determine for you which is damaged and recommend the right repairs.
Loss of voltage at blower motor when it is connected to regulator – regulator is brand new
ANSWER : Hi there. The issue you are having is not the resister, but rather the switch. The switch contacts are shorting out back to the battery causing the a/c blower not to work. I recommend replacing the a/c blower switch. If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from YourMechanic, that can assist you with replacing the switch.
Blower motor resistor melted, replaced it turned on blower motor and it melted again in seconds.
ANSWER : The blower motor that is drawing too many amperes will melt the resistor and wiring. Anytime the resistor is melted you should replace the blower along with the resistor and connections that show any heat damage. If you need assistance with this, consider YourMechanic, as one of our mobile technicians can diagnose electrical issue and help you replace the blower motor and resistor as necessary.
Car A/C won’t stop blowing even with car turned off, can I unplug blower motor resistor ?
ANSWER : Yes, you can disconnect the resistor or the blower motor to stop the power drain. You can do this until you can get it fixed anyway.
Front A/C blower motor working incorrectly.
ANSWER : One sure way to rule out the blower motor itself would be to observe voltage while the issue is happening. If the voltage being fed to the blower motor fluctuates, the problem is on the control side of the circuit and possibly the resistor. Hire one of our mobile experts to swing by and test the electrical system and track down this bug.
Blower Motor only working on highest speed.
ANSWER : You mentioned that you started to smell something. This may be a sign that the blower controller or the resistor was burnt out when it was hooked up wrong. You should try replacing the blower controlling resistor that you hooked up wrong. But like you mentioned, it could also be a fuse problem that has shorted. If you would like to have this looked at, have a certified technician, like one from YourMechanic inspect the wiring and determine what should be done.
where is my blower motor or blower resistor?
ANSWER : The blower motor and blower resistor is located in the right side of the dash under and behind the glove box.
