Why does my blower motor only work on high speed?

Why does my blower motor only work on high speed?

Many, many times a car or truck will come into the shop with the customer complaining that their blower motor doesn’t work, or only works on high speed, etc. This is usually the case after a blower resistor failure on one or more speed settings.

Is the blower motor on a Chevy Silverado working?

Blower Motor does not work on 1 and 2 speed chevy silverado – YouTube I had a Bad Relay. I got one here https://amzn.to/2PSr6fQ It seems the 88-94Trucks have a different system to control the speeds than the 96-00 OBS style Ch…

What should I do if my blower motor stops?

Replace blower motor. If you have a variable speed blower motor, replace the blower motor speed control module. If you have a three or four speed blower motor, remove the blower motor relay. If the motor stops, replace the relay. Alldatadiy.com and Eautorepair.net are professional-grade shop manuals—period.

What happens when a blower motor resistor fails?

The blower motor resistor is the component directly responsible for controlling the blower motor fan speed. If the resistor shorts or fails, it may cause the blower motor to remain stuck on one fan speed.

Many, many times a car or truck will come into the shop with the customer complaining that their blower motor doesn’t work, or only works on high speed, etc. This is usually the case after a blower resistor failure on one or more speed settings.

Blower Motor does not work on 1 and 2 speed chevy silverado – YouTube I had a Bad Relay. I got one here https://amzn.to/2PSr6fQ It seems the 88-94Trucks have a different system to control the speeds than the 96-00 OBS style Ch…

What are the symptoms of a worn out blower motor?

One of the symptoms of a worn out blower motor is that it can intermittently produce a loud screeching noise when running. How to test a blower motor? If the blower motor doesn’t work at all, the blower motor itself must be tested first. Typically it’s done by measuring the voltage at the blower motor connector when it’s turned on.

What to do if your Chevy S-10 blower does not run?

The other 2 does fine. 1993 chevy s-10 2wd truck, no heat nor a/c, compressor does not run regardless of switch position. This has happened to me as well. The fix is a simple $18-$25 part, the Resistor Block, which is located inside the back Firewall adjacent to the Blower Motor Housing. Two (2) screws and it pops right out.

How does a blower motor resistor control the fan speed?

The blower motor resistor controls the fan speed of the blower motor and the resulting change in air pressure produced by the movement of the blower fan. It accomplishes this by regulating the electric current that powers the motor.

What are the symptoms of a failed blower motor resistor?

Blower motor resistor problems. Problems with a blower motor resistor are common in many cars. The most common symptom of a failed blower motor resistor is when the heater fan only runs at high speed and doesn’t work at low speeds.

How does a relay work on a blower motor?

Finally, with the fan switch on the highest speed, the fan motor is receiving system voltage (14.5 with the engine running). Some systems will energize a relay when the switch is set at the highest fan speed. The relay then closes its contacts, feeding full voltage to the fan, because a relay can handle the current better than the fan switch.

What to do if your blower motor wont start?

You can test by testing with a voltmeter set to “Volt AC” between the high-speed blower wire (usually black) and the white neutral wire. If you are getting 120 volts to the motor and it is not starting then you have a blower motor problem and either need another new blower motor or a new blower motor run capacitor.

Why does my fan blower not come on?

If it does not come on then you might have a control board fan relay that is not sending 120 volts to the blower motor or a bad blower motor winding. You might try to change wires (speeds) on the blower motor to see if that fixes the problem.

How can I tell if my blower fan is a relay?

The only way to test and see if it is a blower motor relay would be to test with a voltmeter to see if the motor is getting 110 volts to the motor when it starts going off and on. I hope you can easily find and fix the problem.

What’s the problem with my blower motor fan speeds?

Probably a bad blower motor resistor you have there, or possibly a faulty blower motor or switch. The most common thing would be the resistor assembly, as that goes out more often than the other parts. A quick check with a test light can determine failure. No Heat In My 2000 Chevrolet Malibu – Blower Not…

Why is the resistor not working on my blower?

Hi There, The resistor is what controls the speed of the blower motor, not the relay. The blower motor relay supplies power to this motor when you turn the switch to “on” that can sometimes fail. When this happens, you may notice that you will not feel anything blowing out of the vents at all.

Replace blower motor. If you have a variable speed blower motor, replace the blower motor speed control module. If you have a three or four speed blower motor, remove the blower motor relay. If the motor stops, replace the relay. Alldatadiy.com and Eautorepair.net are professional-grade shop manuals—period.

What are the symptoms of a bad blower motor relay?

3. Melted relay. Another more serious symptom of a problem with the blower motor relay is a burned or melted relay. Relays are exposed to high current loads and can sometimes get hot when they develop problems.

Is there a high speed blower motor relay?

Yes there is a high speed relay which sounds like it is out. Here is a guide to help test it and the blower motor wiring diagrams so you can see how the system works with the relay location below as well. Check out the diagrams (Below).

How do you change the blower motor on a car?

Removal of the right side dash trim is usually all it takes to access the heater/blower area of the vehicle. A couple screws later and the resistor is out and unplugged from the blower motor. Installation of the new resistor is just as easy, and has a new harness that plugs into the existing blower motor. Now it gets just a tad more intricate.

How is the speed of the blower motor controlled?

The blower resistor is connected in series to the blower fan motor. This means that the current running through the blower motor, and its’ speed is therefore controlled by the resistor value. The user chooses a fan speed by selecting a speed which then connects one of the resistors in the blower resistor pack.

What are the resistors on a blower motor?

Blower resistors are made of several resistors with different resistances. There are also two additional circuits used for the off state of operation as well as the highest speed of operation. In the off state, the blower motor is effectively disconnected from the power supply.

How to test an automotive blower fan motor?

Blower Fan Works on High Only 1 Locate the Resistor The location of this resistor is usually near the blower motor itself which cools the unit when it’s in operation. 2 Test the Resistor Use a grounded test light and locate the outgoing wire from the resistor to the blower motor (usually orange or red). 3 Replace the Resistor

Why does my blower fan only work on one speed?

by Lee Sallings. The most common symptom of a faulty blower motor resistor is a blower fan that only works on one speed, usually high. This can be annoying, but troubleshooting is easy. If you start at the blower motor, and check resistance in the circuit, you will find the problem in no time.

Hi There, The resistor is what controls the speed of the blower motor, not the relay. The blower motor relay supplies power to this motor when you turn the switch to “on” that can sometimes fail. When this happens, you may notice that you will not feel anything blowing out of the vents at all.

Why does my blower motor make a squealing noise?

The squealing noise happens most often in the winter during cold startups and may disappear as the motor heats up. If you ignore the noise, the bearing will continue to wear to the point where the motor won’t start at all. The reason I’m not including the motor resistor as a suspect is because it usually only controls the lower speeds.

Why does my blower not work at high speeds?

Blower works on slow speeds, but not on high speed. Check for bad fuse or bad high speed relay. Swap the high speed relay with another relay with the same part number. Also, check the fuse for the control side of the high speed relay. Make sure the ground side of the high speed relay is working. Blower works on some speeds but not others

How can I tell if my blower speed switch is faulty?

Test for power at all the blower speeds by moving the blower speed switch through all positions. A faulty resistor loses power at different positions on the switch. High blower speed has direct power to the motor from the switch. If there is no power indicated on high blower speed, the problem is most likely the switch or the fuse.

What should I do if my blower motor is not working?

If it’s good, refer to a wiring diagram for your vehicle and conduct these tests: Disconnect the electrical connector at the blower motor and jumper power and ground to the motor, bypassing all the speeds controls.