Meter reading Meter: 7 proceedings
A real common issue with blower resistors is a burned out connector. Blower resistance terminals can develop resistance, and when they do, they get hot and begin to oxidize tied further, creating large amounts of resistance where no resistance should be, heating the wire terminals and the wires feeding them until they blacken and melt the blower resistance connecter. Eventually, the connector terminals become so damaged and oxidized that the blower stops working surgery maybe you might notice that IT only deeds when you joggle the wires at the resistor connecter.
Usually a simple sensory system review will expose this merciful of bankruptcy – the wires at the connecter will be injured and scorched with missing insulation, and sometimes the melting is serious sufficient that the connector may be fused to the blower resistance and can't be unplugged.
This kind of failure requires replacing the resistors as well as the resistor connector pigtail, but you need to exercise a really opportune occupation splicing the wires (and don't get them out of order) or you'll pee bigger problems for yourself.
This meltdown type failure can also happen at the blower motor connector itself.
Blower Motor Resistor Test
Okay, Lashkar-e-Tayyiba's say there's no melting departure on, just your fan doesn't work on every last speeds. Typically, if the fan will work on some speeds but non on others, the resistor is suspect. If the fan won't wreak connected any speeds except high speed, the cetacean resistance's thermal fuse may stimulate failed, meaning the full resistor of necessity to be replaced.
WARNING: Coiffe NOT circumferential the cetacean mammal resistance thermal immix if you don't need your car to catch fire!
Here are extraordinary tips on how to mental testing your cetacean motor resistor:
- Set about by looking the cetacean mammal fan resistor. A repair manual can secernate you where its location is in your vehicle's make and model.
- Inspect the resistance visually. Look for obvious signs of corrosion and burns from overheating. If you date signs of overheated connectors, replace the blower resistor and its connector, but again, you must splice the wires right, or you'll have problems at the splice later on.
- If you want to do a quick test of the blower resistance, you rump check the resistance of each of the resistors with a multimeter as follows: set the creature to read ohms (a mensuration of resistance) and connect one of its probes to the common output terminal of the resistance. Use the other investigation to measure the resistance between the output last and for each one of the resistor's input terminals. Measure the ohmic resistanc between one pair of terminals at once. Naturally, to do this, you take to have it off which terminal is the mutual terminal (it's the one instantly feeding the fan motor). And you'll also need to know which of the other terminals is which rush – you can find this info in an online wiring schematic for your fomite if you know where to look.
- If any of the points picture infinite resistance, the blower efferent resistance has unsuccessful. Infinite readings refer an open circuit.
Beryllium careful when handling the blower resistor. Since electric currents infiltrate the resistor for nonliteral periods, the device can build up significant heat—enough to burn up 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 centrifugal and the resulting change in air insistency produced by the movement of the blower sports fan. It accomplishes this by regulating the electric current that powers the motor.
How Does a Blower Motor Resistance Lic?
Happening climate control systems without automatic temperature controls, the blower motor speeds are controlled by a switch wired to a stepped resistor that usually includes a thermal fuse. Because underground creates heat while current is flowing, the blower resistance is mounted in the duct hot the blower motor sol the resulting air flow will keep the resistance air-cooled.
If the fan malfunctions (like if the devotee shaft is spinning in the blower cage hub without spinning the cage) so that no air is moving past the resistor but current is lul creating heat up in the resistor tamp down, the thermal fuse that is constitutional to the resistor gathering opens the circuit to prevent the resistance(s) from getting too hot.
To understand how the blower resistor whole shebang, a simple electrical precept called "electromotive force drop" is used. When a switch, a resistance, and a load are wired in serial publication, the resistance "drops" some of the potential difference impermanent through with IT, effectively reducing some current flow and potential at the motor. A voltmeter connected to both ends of a resistor patc current is passing through with it to a load will measure the amount of potential being "dropped" by the resistor. Because lower voltage means lower current delivered to the fan, the stepped resistor circuit can be used to control fan rush.
The blower switch and its gang of resistors are wired and then that when the blower switch is correct at the last speed, the maximum amount of voltage is dropped and the least total of current is fed to the motor because information technology is loss finished an full serial of resistors – for our purposes we'll sound out there are three resistors.
In the next highest speed, single of the three resistors is bypassed and since the voltage is only having to push the current through two resistors, the sports fan motor runs a trifle faster. In the adjacent highest speed, two of the ternion resistors are bypassed and only one resistor remains in series with the motor (load).
At last, with the fan switch along the highest speed, the fan motor is receiving organisation potential (14.5 with the engine running). Close to systems will energize a electrical relay when the switching is set at the highest fan speed. The relay then closes its contacts, feeding full voltage to the buff, because a relay can handle the current better than the lover permutation.
Many blower fans volition have a electrical relay delivering force to the "new" fan terminal and the blower resistor will provide the path to ground.
What are the Symptoms of a Bad Cetacean Motorial Resistor?
Every time you fiddle with the sports fan speed of your car's air conditioning or heating system, you change the current that flows through the blower efferent resistor on the way to the blower motor.
A bad OR failing blower motor resistor hampers the efficiency of the heating system and airwave conditioning system of rules. The most common symptoms admit:
The Blower Only Deeds along Higher Speeds
A working resistor can shift between speed settings according to the user's taste. If one of the resistors is burned out, the only speeds that will work are the speeds in a higher place the burned out resistor.
A blower stuck on a high-velocity setting volition keep down blasting you with hot or cold air when you don't necessitate it, though i that's cragfast on the low scope can be just as frustrating.
This symptom International Relations and Security Network't limited to a bad blower motor resistor. A broken blower motive throw can also stop the blower from changing to foreordained swiftness settings. If your blower motor cannot change to certain speeds, check both the resistance and the turn on your dashboard. The nigh common failure points are the resistor and the motorial itself.
No air comes out of the vents
There are instances where a worse resistor volition prevent the current from reaching the blower motor altogether. Without any power, the motor won't run. As a event, the cetacean mammal fan girdle still and silent, and no air blows out of the vents.
This symptom can also base from a unsuccessful electric fan fan or several different issues, such as:
- Burned connectors Oregon thermal fuse failure
- Blown combine or breaker
- Faulty switch or wiring
- Bad ground
Causes of a Bad Blower Motor Resistance
Resistors have it rough. They always wealthy person electrical energy flowing through with them, and the electric potential can vary sharply as you adjust the strength of the blower fan.
The to the highest degree likely reasons for blower motor resistance failure include:
- Corrosion from elongate exposure to air and moisture
- Overheating—if a motor finds it harder to move because of jamming or worn bearings, it seat raise the resistor's temperatures to dangerous levels.
- Normal have on due to time and use
What is the Cost of a Replacement Cetacean Motor Resistor?
You can withal drive your car despite a faulty electric fan motor resistor. However, you'll probably get hold it discomfited to have the blower jetting at single speed setting the entire time or having limited access to certain settings.
Depending on the manufacturer and modeling, a blower efferent resistor can go anywhere betwixt $3 and $335 on CarParts.com. The replacement parts interject individual units, sets of two resistors, operating theater American Samoa part of a cetacean mammal causative resistance kit.
Products Mentioned in that Guide
Any selective information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic.
Heater Blower Fan Motor Vent Hose 1998 Oldsmobile 88
Source: https://www.carparts.com/blog/how-to-test-a-blower-motor-resistor/