2012 Ford Escape Fan Only Works on High
Blower efferent, resistance: how it industrial plant, symptoms, problems, testing
Updated: August 01, 2022
The motorial that runs the fan in the heating plant and air travel conditioning system in a car is called a blower motor. It's located inside the shoot, often on the antonym side of the guidance wheel or inside the engine compartment on the firewall. A cetacean mammal centrifugal resistance or a cetacean mammal motorial control module is the part that controls the pelt along of the blower motor.
What is the difference? A blower motor resistor is a simple electrical resistance. It's old in cars where the blower motor has only 4 or 5 fixed speeds, as on the left side in this diagram. Experience the photo of the Fording blower drive resistor.
Cars with an automatic rifle clime control system and vehicles where the cetacean mammal bucket along dismiss be adjusted step by step are equipped with an electronic blower motive control module, see the exposure.
In most moderne cars, the blower motor resistor or the control module are installed inner one of the ducts in the HVAC system, close to the blower motive. This is done, indeed the resistor or a control module is cooled down by impermanent air. In some older cars, a blower motor resistor was installed on the firewall with access from under the hood.
Cetacean mammal motor resistance / control module problems
Problems with a blower motor resistance are common in many cars. The all but common symptom of a failed blower motor resistance is when the bulle fan only runs at the highest speed setting (4 or 5) and doesn't work on low speeds. In some cars, a failed blower motor resistance give notice cause a heater lover to stop working completely.
In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an undue electrical flow that can overheat and untimely damage the blower motor resistor. For model, this happens when the lover blade is jammed away a abroad object or when the motor bearings are fatigued and it doesn't spin freely.
Problems with a cetacean mammal motor control mental faculty are less regular, but it fails for the same reason: due to corrosion operating room overheating when the motor is jammed or shorted. In most cases when a blower control faculty fails, the blower motor doesn't work on all. In some cars (e.g., old GM trucks), a failed blower control module or processor potty cause the blower motor to continue continual even with the inflammation Slay.
How is the blower motor resistor diagnosed?
This Ford blower motor resistor has failed due to corroding
Diagnostic procedures alter. Often a visual review of the resistor reveals the problem. For example, as you can buoy see in this photo, the blower motor resistor therein Fording Escape has failed due to corrosion.
If the resistor shows no visual damage, the resistance between terminals must be checkered and compared to specifications. If the resistance is taboo of specs, the resistance must be replaced.
For example, therein photo we sounded the resistance of this blower motor resistor. According to the Robert William Service manual, IT must be around 4-5 ohms.
Unsuccessful resistor tested with an ohm-meter
In our case the ohmmeter shows hospitable circuit, which means the resistor has failed.
Sometimes, a blower motor resistor might fail due to problems with the blower motor itself. This means after replacing the blower motor resistor, check if the blower motor runs freely and doesn't make any noise. We bear seen instances where a worn-down cetacean motor causes a recently replaced resistor to fail again. For instance, this matter was common in older Chrysler and Dodge minivans. In this case, the blower centrifugal must besides be replaced. One of the symptoms of a worn taboo blower motor is that it can intermittently bring out a loud screeching noise when running.
How to test the cetacean motive?
If the blower motor doesn't put to work in the least, the blower motor itself essential be tested first. Typically it's through with by measuring the voltage at the blower motor connector when it's turned happening. If there is a voltage at the motor (at least 4-6 Volt at down fastness and 12 V at high fastness), but the motor doesn't lean, the motorial is bad Oregon jammed.
Testing the voltage at the blower motor. If there is a voltage at the motor (at to the lowest degree 4-6 V at low speed and 12 Volt at high zip), but the motor doesn't run, the centrifugal is bad.
Things like leaves, twigs, nuts, pieces of a ripped cabin filter can jamming the blade of the blower causative. This happens often in galore cars.
If at that place is no voltage at the motor, the entire blower motor circuit essential be tested, starting from a fuse. See: how to check a mix up in a motorcar.
If a blower motor is rotten, it wish need to glucinium replaced. The blower motor replacement costs from $320 to $650, dependent on the railroad car. In many an cars it's passabl easy; the blower motor is located nates the glove box and held by 3-4 screws. In others it might represent located inside the dash (e.g. Mazda 5) which makes replacing difficult.
If you need a becoming diagnostic technique, we have posted several golf links where you can access a table service manual for your car for a subscription fee. Suss out this post, scroll down the Page.
How is the electric fan motor control module tested?
Mechanics at a dealership can name the HVAC system with a scan tool. If the skim tool is not available, in umteen cars with an automatic climate keep in line system there is a self-examination or diagnostic fashion.
Typically it can be reactive by imperative and holding different buttons. For model, in the 2009 Honda Accord, the service manual describes the procedure as follows: Turn the inflammation to ON. Press and hold the Soured button and within 10 seconds press and release the Window Defogger release five multiplication. The system enters the self-diagnostic mode and at the end of it, if there is a trouble, the demerit code will be displayed along the display. The service blue-collar describes the testing operation for from each one code. See, for example, these YouTube videos; add make and model of your fomite.
Another way is to check the potential at the blower motor, the blower motor curb module and other parts of the circuit accordant to the service manual. E.g., in the mentioned 2009 Honda Allot, the + 12V power is supplied like a shot to the blower motive through the fuse and so through the relay.
Examination Honda big businessman transistor (electric fan motor control mental faculty).
The blower efferent control module (Honda calls it Mightiness Transistor) supplies the ground. The power transistor has 4 wires: two come from the mood control system keep in line unit, one is the ground, one goes to the negative terminal of the blower motor. The service of process manual advises measurement the voltage at the cetacean mammal causative, then if non Okay, at the power electronic transistor and then on.
A failing power transistor was a passabl common cause for not working blower causative in some Honda and Acura vehicles. For example, the Honda bulletin 03-048 described a problem where the blower motor for the rear HVAC system in the 2003 Pilot would non bring on in the least speeds.
Honda blower motor master module (power transistor)
The bulletin recommends replacing the rear power transistor as a solution.
BMW calls the cetacean mammal motor control module a Final Stagecoach Unit, which is also within reason common to fail. Sometimes it doesn't fail completely, but causes the blower drive to hitch operative intermittently or run at individual speeds. See these YouTube videos for more information.
In some GM trucks, a blower motor controller module failure terminate cause the front blower motor to stop working Oregon run after the vehicle has been shut off. The GM bulletin 06-01-39-002C describes this trouble that happens in cold weather. The bulletin advises replacing the cetacean motor control module. Gram calls it Additive Power Module (LPM). Watch these YouTube videos for Thomas More information.
Repair options
Your local auto-mechanic or some small repair frequent should be fit to diagnose the problem. Naturally, the quickest mode is to make an appointee with your dealer. Many an dealers have the part in stock. The blower motor resistor Beaver State control faculty replacement is not very dear.
For example, one of our colleagues had a problem with his 2011 Ford Escape: the fan exclusive worked at the belt along 4. He paid $50 to diagnose and $112 to replace the resistor at a local Ford franchise. When the same problem occurred two years later, he ordered the part online for $25 and replaced information technology himself.
In the 2008-2011 Ford Get away / Mazda Tribute, the blower efferent resistor is settled on top of the HVAC unit of measurement, down the mit box.
In the 2008-2011 Ford Escape, the resistor is settled prat the glove box happening top of the HVAC unit air channel. It's held aside two screws and is effortless to replace. See the photo.
In the 2008-2011 Ford F150, the blower centrifugal resistor is likewise located behind the glove box, but is installed on the right side of the plastic air duct. This thread at f150online.com shows where the resistance is placed.
The author of this blog shared out his experience of replacing the cetacean mammal motor resistor in Jeep Liberty. In few older cars and trucks, the blower motor resistor is installed connected the firewall, with access code from subordinate the exhaust hood.
How the blower motor resistor deeds
Typical blower resistance diagram
This plot shows how the cetacean motor resistance is connected in a typical car. In this car, in the highest "4" fan speed setting, the resistor is bypassed and the cetacean efferent is powered directly by the fan switch. That's why in around cars, the blower motor may notwithstandin work in the "High" bucket along setting if the resistor is bad.
In this diagram, the fan switch is set to the speed "1", so the blower efferent current is reduced by three resistors (R2 + R3 + R4) connected in series. The current flow is shown in blue and red.
In the setting "2", there are two resistors connected serial, and in "3", there is only one resistance.
Adding resistance to the galvanizing circuit reduces the current in the electric circuit. When several resistors are connected in series, the unconditional resistance increases and is adequate the sum of individual resistances.
2012 Ford Escape Fan Only Works on High
Source: https://www.samarins.com/glossary/blower-motor-resistor.html
