Why does my car heater only work on one setting?
Most car manufacturers use a series of resistors to make the heater blower motor run at different speeds. And when one or more of these resistors burn out, you’re usually left with only one heater blower motor speed—high. The resistor module is easy and inexpensive to replace.
Why does my blower motor only work on low speed?
Odds are good that the fan switch may be at fault, but a more likely reason is that a blower motor resistor that controls the voltage going to the blower has packed it in, resulting in only one speed remaining operable — usually the highest speed, which you may not always need depending on the temp of the outside air.
Why does my fan blower only work on high?
When a blower resistor fails, the highest fan speed usually is the only one that still works because it essentially bypasses the resistor and receives the maximum amount of voltage. When the resistor is working, it reduces the amount of voltage going to the lower fan speeds so the fan runs slower.
What are the signs of a failing blower motor resistor?
Signs of a Bad Blower Motor Resistor
- Loss of HVAC fan control (total or certain speeds)
- The fan only works on its highest speed setting.
- No air coming from vents.
- Intermittent or inconsistent fan speed.
How much does it cost to replace a blower motor resistor?
between $50 to$150
How much does a blower motor resistor cost? To replace the blower motor resistor, it would cost you anywhere between $50 to$150 – this includes the cost of equipment and labor. However, by doing it yourself at home, you can save up to $70.
Can you repair a blower motor resistor?
The average cost to replace the blower motor resistor at a repair shop is between $44 and $55 in parts and $70 in labor costs, for a total cost of around $114 to $125. On the other hand, you can easily fix the blower motor resistor at home in about an hour (even if you’re a beginner) and for around $70.
What controls the blower motor speed?
Blower resistors
Blower resistors are resistors which are used to control the fan speed of automotive blowers. The fan speed can be changed either by switching the blower resistor resistance mechanically using a rotating lever, or electronically by the air conditioning system.
What controls the blower speed?
blower motor resistor
The blower motor resistor is responsible for controlling the blower motor speed. In the past, this was done by varying the voltage supplied to the blower motor. In newer applications, the blower motor resistor is actually a solid state module that sends a varied signal to the blower motor.
Why does my heat and air only work on high?
The blower motor resistor is prone to shorts, corrosion, and overheating. When the resistor fails, typically, the highest setting is the only option that still functions. This is because the air from the blower motor is bypassing the resistor, thus gaining the maximum amount of voltage, resulting in full power.
Why does my fan only work on one speed?
If the fan only runs at one or two speeds, then it has a defective capacitor. Once the multiple section capacitor malfunctions, it prevents the fan from operating properly. Oftentimes, you can do nothing with this but replace it with a new one.
Is there a fuse for blower resistor?
A fuse is often located on the resistor board. The fuse only protects the low and medium blower speeds. High speed will still work if the resistor fuse is blown.
What happens when a blower motor relay goes bad?
If the blower motor relay develops any sort of problem that hinders its ability to properly limit and distribute power, it may cause the blower motor fuse to blow. Any sort of electrical spikes or excessive current from a bad relay will blow the fuse and cut power in order to protect the system.
Should you replace blower motor and resistor at the same time?
We do suggest that you replace the resistor at the same time. It may not be critical, but this will keep the system more uniform. The issue may even be related to the resistor. If you know that it is not related to the issue, then you do not have to replace it.
How do I reset my blower motor?
How to Find and Reset your Furnace Motor Blower
- Step 1: Turn off the power to the furnace.
- Step 2: Remove the blower compartment cover.
- Step 3: Make sure the blower is completely cooled off.
- Step 4: Locate the reset button.
- Step 5: Press the button in (assuming that this is your issue and that the button has popped).
Can you adjust blower fan speed?
Once you cut the power, you can remove the cover of your furnace to get access to the control board. Adjusting the pulley on the blower driver motor lets you increase or decrease the blower speed. Refer to your owner’s manual to find out exactly what the pulley and other applicable parts look like.
How do I control the fan speed on my blower?
You can increase or decrease the blower speed by slightly adjusting the pulley on the blower drive motor. To increase blower speed, slightly loosen the setscrew that holds the pulley to the driveshaft. Move or turn the pulley clockwise on the shaft one turn, then tighten setscrew.
What controls the blower motor speeds in a heater system?
A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.
Where is the blower resistor located?
It’s located inside the dash, often on the opposite side of the steering wheel or inside the engine compartment on the firewall. A blower motor resistor or a blower motor control module is the part that controls the speed of the blower motor.
Why is my fan not going full speed?
If you can’t change the speed of your ceiling fan, it may be because of a broken pull chain or damaged chain switch assembly. Both are easy to replace, but replacing the assembly involves cutting and splicing some wires. Another possibility is a blown or faulty capacitor or a faulty fan speed regulator knob.
How can I override my fan speed?
How to adjust fan speeds using software
- In the configuration menu, head over to Fan Control.
- Check the box next to Advanced Fan Control.
- Click on the Add box located on the right.
- Name the Fan Controller the group of fans you want to adjust.
- Select Controlled Speed.
What fuse controls the blower fan?
To protect the blower motor power circuit, a 20-, 25- or 30-amp fuse is usually located in the fuse panel under the dash. The rating of the fuse will depend on the vehicle application and how much power the blower motor requires at full speed.
How can you tell if a fan fuse is blown?
Look at the fuse wire. If there is a visible gap in the wire or a dark or metallic smear inside the glass then the fuse is blown and needs to be replaced.
How do I test a blower fan relay?
Connect a test light or multimeter to the ground (black lead). Turn the ignition key to the on position (engine off), and remove the relay. Using the probe, test all terminal sockets in the relay connector. Two of the four should have power.
How do you know if a relay is faulty?
If your starter relay has gone bad, the electrical signal will never make it from the battery to the starter motor. As a result, your engine won’t turn over – no matter how many times you turn the key. A faulty relay often produces an audible clicking sound when you turn your car.
What happens when a blower motor resistor goes bad?
A common symptom of a faulty blower motor resistor is a blower motor that is stuck on one setting. 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.