Blower motor resistor has repeat failures. This electrical component is used to control the air conditioning system of a vehicle. Basic instructions on how to troubleshoot the heater blower motor of a Saturn S-series. I have no blower at any speed 01 T&C Ltd with ATC. Be sure, when testing the resistor, to also check fuses, relays and voltage. It is my understanding that at the highest fan speed, there is 0 ohms resistance upstream of the blower motor. At high speed, the resistor is bypassed, and power comes directly from the switch. The a/c compressor will click on but then shuts off which leads me to suspect the blower motor I checked obvious fuses all good. How To Test Ac Blower Motor Resistor. If not OK, replace the faulty blower motor resistor block. (The black wire is usually the negative.) A 1/4-inch socket will be needed to remove the screws holding the cover. The blower resistor is one of the many obscure parts in your car. Make sure you have power to the dark green wire from the relay to the motor (key on). The air conditioning and heating controls allow you to switch fan speeds — and the blower motor resistor controls that speed once you select it. Test the blower to see if it works properly. This bad boy is a breeze to test since it's located under the dash and not that hard to access (unlike the 2000 and earlier Dakota and Durangos which have it … Good evening, To test the blower motor resistor, unplug the resistor connector. The blower motor resistor is the component directly responsible for controlling the blower motor fan speed. Check for full airflow at the vents. The blower motor is a D/C electric motor driven by varying current supplied by the blower motor final stage unit. The blower motor relay controls the current used to power the blower motor, and is subject to the constant on and off switching. BM that draws more than 10A is not good and will cause regulators to fail. The blower motor resistor assembly, on your 3.9L Dodge Dakota, is tasked with reducing the current that the blower motor uses. Is it the front blower motor you are working on? The blower motor resistor is an electrical component that is a part of the vehicle's heating and air conditioning system. The other is by bypassing the blower resistor with a jumper wire and thus indirectly testing the blower resistor assembly. Reconnect the negative cable to the battery. Just to the left of the blower motor, an electrical connector connected to a flat 1-inch-by-2-inch plate can be seen. How to test a heater blower motor resistor The heater a/c blower motor in my wife 2000 Acura TL seems to have failed. This can be a bad blower motor resistor or a failed speed switch. Your car doesn't have a resistor pack for the front blower motor it uses PWM (Pulse Width Modulation) to control motor speed. The problem is with the blower motor, and it needs to be replaced. The less current the blower motor uses, the slower it runs. How does the heater blower motor resistor work? The blower motor resistor adjusts the blower motor's speed. In this video you'll learn how to find, test, and if need be replace the blower resistor in a 2002 Dodge van. It uses resistance to control the speed of the blower motor. Log In Sign Up. With that said, failed blower resistor assemblies don't solve all of the possible failures. (The rear aux blower does still use a resistor pack). If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed. When the blower motor relay does begin to fail, the vehicle will usually display a few symptoms that alert the driver of a potential problem that should be serviced . Part 1 How To Test The Er Motor … This means that the current running through the blower motor, and thus is speed is controlled by the resistor value. Standard® offers over 700 blower motor resistors as high-quality replacements that match the OE to ensure top performance. I recently (3-4 months back) replaced the blower motor resistor in my 2002 325i. How do I test if it’s the motor or the resistor before I buy the part? If the resistor is bad you really need to consider the strong possibility that the resistor failed because of an aged and dragging blower motor. If your blower motor fails, replace the blower and resistor together. Testing: Verify the fan is intact and it spins without much resistance (bearings go bad in these things when they get age on them). Continue checking each resistor in the resistor box. Access to the relay & blower is from under the dash on the passenger side. To test blower motor, you need car battery and current meter that can go up to 20A. The motor can be seen hanging down close to the passenger kick panel. The user chooses a suitable fan speed by using a selector to connect one of the resistors in the blower resistor pack. I'd like to fix it right, of course, but: 1. If so the transistor is contained in the module on the side of the blower motor housing as shown in the diagram below. A blower motor resistor is an adjustable resistor. Reattach the harness on the box, then secure the box on the motor with the screws. Hereof, how do you troubleshoot a blower motor resistor? The blower motor resistor (or final stage) varies voltage to the blower motor to achieve the desired speed. Each blower motor switch input terminal on the resistor must have continuity to the resistor output terminal, which is connected to the circuit going to the blower motor. If they are then replace the plug and resistor. It takes some time to kill them, but with BM drawing >10A, you will get into a syndrome of replacing regulators and this occurs far too often. That means the resistor & switches are on the ground side that controls the on-off & speed of the motor. Using a multimeter set on the Ohm scale, use the positive lead and test the black wire. The good news is, dropping the blower motor is easy and can be done in just 30min or so. This tutorial will help you test the 2001-2004 Dodge Dakota and Durango blower motor resistor in a step-by-step way. The heater blower motor is located behind the glove compartment of your vehicle. From the passenger foot well area, remove the two hex screws used to secure the blower motor resistor. In cases like this even when you replace the blower motor resistor the blower motor itself may still be struggling and cause the resistor to fail again quickly despite being a new part. With an ammeter you could test the current draw with the blower motor on the HIGH position. Then replace the VBC or resistor (whichever you have) and the motor if necessary, and you're all set. Tapping on the blower of wiggling the connector will usually allow the 2 ends to make contact long enough to get the motor turning again. Locate the blower motor. The rest of the circuit is the grounding side of the motor. The resistor is between the power source and the fan, and allows only the desired amount of power to go to the fan. Press J to jump to the feed. Reinstall the lid on resistor box. The resistor is what controls the blower motor speed by restricting electricity through either the … You don't want to have to go back in if one fails later. Over time, it can eventually wear out . If the blower motor resistor continuity does not check OK, replace the faulty resistor . Because the voltage passing through the resistor is adjusted and lowered … masuzi 4 years ago No Comments. The blower motor is the component responsible for … Test the blower motor relay-if okay Apply direct power from the battery to the blower motor-don't come On-test the blower motor resistor-if okay the last stop will be the HVAC control module/blower … If the motor is pulling a large amount of current (say 20 amps or more) then the motor is on the way out also. How to Troubleshoot a Blower Motor Resistor. Unplug the blower motor and see if there is voltage (fan on high should be the full 12 volts) If there is none, unplug the resistor and first look if any of the termanals are burnt/melted. This morning I get in the car and no fan. It is responsible for controlling the blower motor’s fan speed. User account menu • How do I test a blower motor. Here is the information on replacing the resistor: REMOVAL Disconnect and isolate the battery negative cable. The blower resistor is connected in series with the blower fan. This illustration shows a typical blower resistor, specifications, and test procedures vary between different manufacturers. Press question mark to learn the rest of the keyboard shortcuts. I called the dealer and he said there is a warranty on the resistor pack. Ford blower motor resistor problems remain the most common solution to interior fan malfunctions on Ford cars and trucks. The front blower speed is controlled by a power transistor not a resistor. Would it be safe to shunt/jumper/short the blower motor resistor, provided I am content with having the fan on full blast? Part 1 how to test the er motor part 1 how to test the er motor part 1 how to test the er motor how to replace a er fan motor in. Unplug the front blower motor resistor from the wire harness connector. This is … But for them to honor the warrant they would have to check the resistor pack. Disconnect the negative and positive power supply. In order to test the operation of your blower motor resistor, you’ll be measuring the function by reading the internal resistance. If you find that the fan in your car only works on high, you might well have a broken one. Refer to the wiring diagram for your vehicle and check for continuity on all three resistors and speed switch setttings. If any of them are bad, you should replace the entire box with a new unit. Testing your Chevy Cavalier Blower Motor Resistor. The blower motor relay is the electrical switch that is used to supply the power for the vehicle’s blower motor. By doing so, you can save yourself time and headache by ensuring you fix the right part the first time around. Facebook; Prev Article Next Article . The first test, and probably the most popular way to test the blower motor resistor is by checking the continuity of the resistors that make up the resistor assembly. Locate the fuse for the blower motor in the owners/service manual. 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