It is responsible for controlling the blower motor’s fan speed. Unplug the blower motor and test for power using the 12-volt test light in the same manner as explained in Step 1. If they are then replace the plug and resistor. If not OK, replace the faulty blower motor resistor block. With that said, failed blower resistor assemblies don't solve all of the possible failures. (The black wire is usually the negative.) What makes this reduction in current (and speed possible) is the three resistor coils that make up the blower resistor … The blower resistor is connected in series with the blower fan. 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. Check for full airflow at the vents. How does the heater blower motor resistor work? In order to test the operation of your blower motor resistor, you’ll be measuring the function by reading the internal resistance. The blower motor resistor is the component directly responsible for controlling the blower motor fan 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. 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. Standard® offers over 700 blower motor resistors as high-quality replacements that match the OE to ensure top performance. The problem is with the blower motor, and it needs to be replaced. That means the resistor & switches are on the ground side that controls the on-off & speed of the motor. This morning I get in the car and no fan. 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. To test blower motor, you need car battery and current meter that can go up to 20A. 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. Then replace the VBC or resistor (whichever you have) and the motor if necessary, and you're all set. The user chooses a suitable fan speed by using a selector to connect one of the resistors in the blower resistor pack. The blower motor resistor is an electrical component that is a part of the vehicle's heating and air conditioning system. The blower motor is a D/C electric motor driven by varying current supplied by the blower motor final stage unit. The blower resistor is one of the many obscure parts in your car. If the blower motor resistor continuity does not check OK, replace the faulty resistor . Testing your Chevy Cavalier Blower Motor Resistor. masuzi 4 years ago No Comments. So if you didn't have power there, or you didn't have ground there, the next step, we're gonna test the resistor. A blower motor resistor is an adjustable resistor. But for them to honor the warrant they would have to check the resistor pack. Hereof, how do you troubleshoot a blower motor resistor? How to Troubleshoot a Blower Motor Resistor. If the motor is pulling a large amount of current (say 20 amps or more) then the motor is on the way out also. This illustration shows a typical blower resistor, specifications, and test procedures vary between different manufacturers. With an ammeter you could test the current draw with the blower motor on the HIGH position. 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. This is … Testing: This tutorial will help you test the 2001-2004 Dodge Dakota and Durango blower motor resistor in a step-by-step way. If any of them are bad, you should replace the entire box with a new unit. Basic instructions on how to troubleshoot the heater blower motor of a Saturn S-series. BM that draws more than 10A is not good and will cause regulators to fail. I'd like to fix it right, of course, but: 1. How To Test Ac Blower Motor Resistor. You don't want to have to go back in if one fails later. The blower motor relay is the electrical switch that is used to supply the power for the vehicle’s blower motor. Reattach the harness on the box, then secure the box on the motor with the screws. (The rear aux blower does still use a resistor pack). 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. Refer to the wiring diagram for your vehicle and check for continuity on all three resistors and speed switch setttings. Disconnect the negative and positive power supply. It uses resistance to control the speed of the blower motor. If you find that the fan in your car only works on high, you might well have a broken one. The heater blower motor is located behind the glove compartment of your vehicle. 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. Would it be safe to shunt/jumper/short the blower motor resistor, provided I am content with having the fan on full blast? Reinstall the lid on resistor box. I have no blower at any speed 01 T&C Ltd with ATC. The resistor is between the power source and the fan, and allows only the desired amount of power to go to the fan. Is it the front blower motor you are working on? 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