Verify the fan is intact and it spins without much resistance (bearings go bad in these things when they get age on them). Just to the left of the blower motor, an electrical connector connected to a flat 1-inch-by-2-inch plate can be seen. 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. The air conditioning and heating controls allow you to switch fan speeds — and the blower motor resistor controls that speed once you select it. This is why at the bottom of the article we include a 2008 F150 blower motor wire diagram. How To Test Ac Blower Motor Resistor. Make sure you have power to the dark green wire from the relay to the motor (key on). You don't want to have to go back in if one fails later. 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. In order to test the operation of your blower motor resistor, you’ll be measuring the function by reading the internal resistance. If any of them are bad, you should replace the entire box with a new unit. Blower motor resistor has repeat failures. With an ammeter you could test the current draw with the blower motor on the HIGH position. The blower resistor is one of the many obscure parts in your car. Press question mark to learn the rest of the keyboard shortcuts. This means that the current running through the blower motor, and thus is speed is controlled by the resistor value. Ford blower motor resistor problems remain the most common solution to interior fan malfunctions on Ford cars and trucks. The heater blower motor is located behind the glove compartment of your vehicle. 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 . Is it the front blower motor you are working on? The resistor is between the power source and the fan, and allows only the desired amount of power to go to the fan. The blower motor is the component responsible for … I'd like to fix it right, of course, but: 1. 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. With that said, failed blower resistor assemblies don't solve all of the possible failures. Test the blower to see if it works properly. It uses resistance to control the speed of the blower motor. So if you didn't have power there, or you didn't have ground there, the next step, we're gonna test the resistor. I called the dealer and he said there is a warranty on the resistor pack. The blower motor relay is the electrical switch that is used to supply the power for the vehicle’s blower motor. From the passenger foot well area, remove the two hex screws used to secure the blower motor resistor. Locate the HVAC blower motor resistor and test it to see if this is the issue. The rest of the circuit is the grounding side of the motor. This can be a bad blower motor resistor or a failed speed switch. How do I test if it’s the motor or the resistor before I buy the part? If your blower motor fails, replace the blower and resistor together. Reattach the harness on the box, then secure the box on the motor with the screws. You can see the wiring running from the motor … Locate the blower motor. By doing so, you can save yourself time and headache by ensuring you fix the right part the first time around. If they are then replace the plug and resistor. Then replace the VBC or resistor (whichever you have) and the motor if necessary, and you're all set. If you find that the fan in your car only works on high, you might well have a broken one. Disconnect the negative and positive power supply. Testing your Chevy Cavalier Blower Motor Resistor. How to test a heater blower motor resistor The heater a/c blower motor in my wife 2000 Acura TL seems to have failed. Good evening, To test the blower motor resistor, unplug the resistor connector. This morning I get in the car and no fan. A 1/4-inch socket will be needed to remove the screws holding the cover. Your car doesn't have a resistor pack for the front blower motor it uses PWM (Pulse Width Modulation) to control motor speed. masuzi 4 years ago No Comments. Over time, it can eventually wear out . If so the transistor is contained in the module on the side of the blower motor housing as shown in the diagram below. Reconnect the negative cable to the battery. The less current the blower motor uses, the slower it runs. The blower motor resistor (or final stage) varies voltage to the blower motor to achieve the desired speed. 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. That means the resistor & switches are on the ground side that controls the on-off & speed of the motor. How does the heater blower motor resistor work? BM that draws more than 10A is not good and will cause regulators to fail. 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 … (The black wire is usually the negative.) Hereof, how do you troubleshoot a blower motor resistor? The blower motor resistor adjusts the blower motor's speed. If the blower motor resistor continuity does not check OK, replace the faulty resistor . At high speed, the resistor is bypassed, and power comes directly from the switch. Because the voltage passing through the resistor is adjusted and lowered … This tutorial will help you test the 2001-2004 Dodge Dakota and Durango blower motor resistor in a step-by-step way. Standard® offers over 700 blower motor resistors as high-quality replacements that match the OE to ensure top performance. The user chooses a suitable fan speed by using a selector to connect one of the resistors in the blower resistor pack. The blower resistor is connected in series with the blower fan. It is responsible for controlling the blower motor’s fan speed. I recently (3-4 months back) replaced the blower motor resistor in my 2002 325i. The blower motor relay controls the current used to power the blower motor, and is subject to the constant on and off switching. Basic instructions on how to troubleshoot the heater blower motor of a Saturn S-series. (The rear aux blower does still use a resistor pack). Reinstall the lid on resistor box. User account menu • How do I test a blower motor. 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