Pin Postion and Ohm Reading on Blower Motor Resister for 2010 Gmc Acadia
Reading Time: 7 minutes
A very common issue with blower resistors is a burned out connector. Blower resistor terminals can develop resistance, and when they do, they become hot and begin to oxidize even further, creating big amounts of resistance where no resistance should exist, heating the wire terminals and the wires feeding them until they scorch and melt the blower resistor connector. Eventually, the connector terminals become so damaged and oxidized that the blower stops working or perhaps y'all might notice that information technology only works when you wiggle the wires at the resistor connector.
Usually a simple visual inspection will reveal this kind of failure – the wires at the connector volition be blistered and scorched with missing insulation, and sometimes the melting is severe enough that the connector may be fused to the blower resistor and can't be unplugged.
This kind of failure requires replacing the resistors every bit well every bit the resistor connector pigtail, but yous need to do a really good job splicing the wires (and don't get them out of order) or you'll make bigger problems for yourself.
This meltdown blazon failure tin besides happen at the blower motor connector itself.
Blower Motor Resistor Test
Okay, allow's say in that location's no melting going on, merely your fan doesn't work on all speeds. Typically, if the fan will piece of work on some speeds just not on others, the resistor is suspect. If the fan won't piece of work on any speeds except high speed, the blower resistor'south thermal fuse may have failed, significant the entire resistor needs to be replaced.
Alert: Practise Non bypass the blower resistor thermal fuse if yous don't want your machine to grab burn down!
Here are some tips on how to examination your blower motor resistor:
- Kickoff by looking for the blower fan resistor. A repair manual can tell you where its location is in your vehicle'southward make and model.
- Inspect the resistor visually. Look for obvious signs of corrosion and burns from overheating. If you see signs of overheated connectors, supervene upon the blower resistor and its connector, but again, you must splice the wires right, or you'll take problems at the splice afterward.
- If you want to exercise a quick exam of the blower resistor, you can check the resistance of each of the resistors with a multimeter equally follows: set the tool to read ohms (a measurement of resistance) and connect one of its probes to the mutual output terminal of the resistor. Utilize the other probe to measure out the resistance between the output terminal and each of the resistor'southward input terminals. Measure the resistance betwixt one pair of terminals at a time. Of grade, to practise this, yous need to know which concluding is the common terminal (it's the one directly feeding the fan motor). And you lot'll also need to know which of the other terminals is which speed – you can discover this information in an online wiring schematic for your vehicle if you know where to look.
- If any of the points show infinite resistance, the blower motor resistor has failed. Infinite readings denote an open circuit.
Be conscientious when treatment the blower resistor. Since electric currents laissez passer through the resistor for extended periods, the device tin build up pregnant oestrus—enough to burn your fingers or worse.
What is a Blower Motor Resistor and What Does it Do?
The blower motor resistor controls the fan speed of the blower motor and the resulting change in air pressure produced past the motility of the blower fan. It accomplishes this by regulating the electric current that powers the motor.
How Does a Blower Motor Resistor Work?
On climate control systems without automated temperature controls, the blower motor speeds are controlled by a switch wired to a stepped resistor that normally includes a thermal fuse. Because resistance creates oestrus while current is flowing, the blower resistor is mounted in the duct almost the blower motor so the resulting airflow will go along the resistor absurd.
If the fan malfunctions (like if the fan shaft is spinning in the blower muzzle hub without spinning the muzzle) and so that no air is moving past the resistor only current is all the same creating rut in the resistor pack, the thermal fuse that is integral to the resistor associates opens the electrical excursion to foreclose the resistor(south) from getting likewise hot.
To understand how the blower resistor works, a simple electrical principle called "voltage drop" is used. When a switch, a resistor, and a load are wired in series, the resistor "drops" some of the voltage passing through it, effectively reducing both current menses and voltage at the motor. A voltmeter connected to both ends of a resistor while current is passing through information technology to a load will mensurate the amount of voltage being "dropped" by the resistor. Because lower voltage means lower current delivered to the fan, the stepped resistor circuit tin can exist used to control fan speed.
The blower switch and its gang of resistors are wired so that when the blower switch is ready at the lowest speed, the maximum amount of voltage is dropped and the least corporeality of current is fed to the motor because it is passing through an entire serial of resistors – for our purposes we'll say there are three resistors.
In the next highest speed, ane of the 3 resistors is bypassed and since the voltage is only having to button the current through ii resistors, the fan motor runs a fleck faster. In the next highest speed, two of the three resistors are bypassed and only i resistor remains in series with the motor (load).
Finally, with the fan switch on the highest speed, the fan motor is receiving system voltage (fourteen.five with the engine running). Some systems volition 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 tin can handle the current better than the fan switch.
Many blower fans will take a relay delivering power to the "hot" fan terminal and the blower resistor will provide the path to footing.
What are the Symptoms of a Bad Blower Motor Resistor?
Every fourth dimension yous dabble with the fan speed of your auto's air conditioning or heating system, you lot change the current that flows through the blower motor resistor on the way to the blower motor.
A bad or declining blower motor resistor hampers the efficiency of the heating and air conditioning system. The most common symptoms include:
The Blower Only Works on Higher Speeds
A working resistor can shift between speed settings according to the user's preference. If one of the resistors is burned out, the only speeds that will work are the speeds above the burned out resistor.
A blower stuck on a high-speed setting will keep blasting you with hot or cold air when you don't need it, though i that's stuck on the depression setting can be merely as frustrating.
This symptom isn't limited to a bad blower motor resistor. A broken blower motor switch can too stop the blower from irresolute to certain speed settings. If your blower motor cannot change to certain speeds, check both the resistor and the switch on your dashboard. The nigh common failure points are the resistor and the motor itself.
No air comes out of the vents
There are instances where a bad resistor will prevent the current from reaching the blower motor altogether. Without any ability, the motor won't run. Equally a upshot, the blower fan stays still and silent, and no air blows out of the vents.
This symptom can too stem from a failed blower fan or several other issues, such as:
- Burned connectors or thermal fuse failure
- Diddled fuse or circuit breaker
- Faulty switch or wiring
- Bad ground
Causes of a Bad Blower Motor Resistor
Resistors accept information technology rough. They always have electricity flowing through them, and the voltage can modify sharply equally yous conform the strength of the blower fan.
The near likely reasons for blower motor resistor failure include:
- Corrosion from long exposure to air and moisture
- Overheating—if a motor finds it harder to movement because of jamming or worn bearings, it can raise the resistor'due south temperatures to unsafe levels.
- Normal wearable due to time and use
What is the Toll of a Replacement Blower Motor Resistor?
Y'all can still drive your car despite a faulty blower motor resistor. However, you'll probably find it uncomfortable to accept the blower running at i speed setting the entire time or having limited access to certain settings.
Depending on the manufacturer and model, a blower motor resistor can go anywhere between $iii and $335 on CarParts.com. The replacement parts come in individual units, sets of two resistors, or equally office of a blower motor resistor kit.
Products Mentioned in this Guide
Any information provided on this Website is for informational purposes but and is not intended to supersede consultation with a professional person mechanic.
Source: https://www.carparts.com/blog/how-to-test-a-blower-motor-resistor/
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