Is there a fuse for heater fan in car?

Yes. In most cars the blower motor that powers the heater (and often the AC) is protected by a fuse or relay in the vehicle’s fuse system. The exact location and labeling can vary by make and model.

Where the fuse typically lives

Fuses for the blower motor circuit are usually found in one of two places: the under-hood fuse/relay box or the interior fuse panel. The labels and amperages vary by vehicle, so consult the owner’s manual or the fuse box diagram if you cannot identify the correct fuse.

• Under-hood fuse/relay box: A dedicated fuse for the blower motor or a climate/AC fuse is common here. Labels may read BLOWER, HVAC, FAN, or A/C. Typical ratings range from 20A to 30A. Some cars power the blower through a relay rather than a separate fuse.


• Interior fuse panel (dash or glove box): A second fuse protecting the HVAC/climate control circuit or blower motor may be located here. Look for labels such as BLOWER or HVAC. Ratings vary widely, commonly 10A–30A depending on the model.


• Climate control module or relay: In newer vehicles, the climate control module can be fused separately, with the blower motor receiving power via a relay controlled by the module.


• No dedicated blower fuse in rare cases: A few designs rely on the main power fuse or a shared HVAC fuse; always verify with the manual for your specific model.

If you cannot locate a labeled fuse, check the vehicle’s manual or fuse box diagrams for the exact names and amperages used by your car’s HVAC circuit.

What the fuse tells you about the blower circuit

Understanding the fuse arrangement helps distinguish between a blown fuse and other failures such as a bad relay, a faulty blower resistor, or a defective blower motor. The following items describe common labeling and amperage you may encounter.

• Common fuse labels: BLOWER, HVAC, FAN, A/C, or CLIMATE. These indicate the circuit powering the blower motor or climate control components.


• Typical amperages: 10A, 15A, 20A, or 30A, with higher ratings more common for newer vehicles or those with higher blower motor loads. Always replace with the exact rating specified for your model.


• Relays and resistors: Some systems use a blower motor relay or a resistor pack; a blown fuse may not always be the sole cause, so inspect adjacent components if the fuse looks intact.


• Signs of a blown fuse: a visibly melted or discolored fuse or a fuse that remains open when tested. Fuses can appear intact even when the circuit is drawing excess current if there is a short elsewhere.

Always start with the fuse as a quick check; if the fuse is blown repeatedly, there is likely an underlying fault in the blower circuit.

How to diagnose a non-working heater fan

To accurately diagnose the issue without unnecessary part replacement, follow these steps. The guidance applies to most modern cars, but always reference your manual for model-specific instructions.

1. Check the blower fuse(s) in both the under-hood and interior fuse panels. If a fuse is blown, replace it with the exact same amperage and monitor for repeat failures.


2. Inspect the blower motor relay (and swap with a known-good relay if compatible) to see if the problem lies in the control side of the circuit.


3. Examine the blower motor resistor (if your car uses one). A failed resistor often causes loss of lower speed settings while high speed may still work.


4. Test for power at the blower motor connector when the climate control is turned on. If power is present but the motor does not run, the motor may be faulty or there could be a grounding issue.


5. Inspect wiring and grounds in the blower circuit for damage, corrosion, or loose connections, especially around the harness and the motor itself.

By following these steps, you can determine whether the fault is a blown fuse, a faulty relay, a defective resistor, a bad blower motor, or a wiring problem. If in doubt, consult a professional technician.

Summary

In most cars, the heater/blower fan is protected by a fuse or relay within the vehicle’s fuse system. Start by locating the relevant fuse in the under-hood or interior fuse panels and replace it with the same amperage if blown. If the fuse holds, investigate the blower motor, relay, resistor, and wiring as potential culprits. When in doubt, consult the vehicle’s manual or seek professional assistance to avoid electrical damage or personal injury.

Why isn't my heater fan working in my car?

A car's heater fan not working is often caused by a blown fuse, a bad blower motor resistor, a faulty blower motor, or a problem with the switch or wiring. You should first check the fuse, and if that is good, inspect the blower motor resistor and the fan motor itself. 
This video explains what to check first when the heater fan isn't working: 57strackpalmerYouTube · Jan 11, 2025
Common causes and solutions

• Blown fuse: This is the most common reason for a complete lack of fan function. 
  • Solution: Check your vehicle's fuse box for a fuse labeled "blower," "HVAC," or "heater" and replace it if it's blown. 
• Bad blower motor resistor: This component controls the fan speeds. If it fails, the fan may only work on one speed (usually high) or not at all. 
  • Solution: Check the resistor for damage or a bad connection. Replacing it can often restore function. 
• Faulty blower motor: The motor itself can fail due to worn parts or an electrical issue. 
  • Solution: You can test for voltage at the motor's connector. If you find voltage but the motor doesn't run, it's likely bad and needs replacement. 
• Broken switch or wiring: The switch that controls the fan speed or the wiring leading to the components can be damaged. 
  • Solution: Inspect wiring for corrosion, loose connections, or other damage. Test the switch for proper function. 
• Debris or obstruction: Leaves, twigs, or other debris can get lodged in the blower motor fan assembly and prevent it from spinning. 
  • Solution: Check for any obstructions in the fan housing and clear them. 
• Other issues: Less common causes include a bad blower motor relay or a clogged cabin air filter, which would restrict airflow but not prevent the motor from spinning. 

You can also watch this video to learn how to test the blower motor: 49sEasyAutoFixYouTube · Jul 9, 2022
What to do if you are unsure
If you are not comfortable working on your car, it is best to take it to a professional mechanic for diagnosis and repair.

What fuse controls the heater blower?

The fuse for a car's heater blower motor is typically a high-amperage fuse (e.g., 20, 25, 30, or 40 amp) found in the interior fuse box, often under the dashboard near the steering wheel, or sometimes in the engine bay fuse box. You can find its exact location and rating in your vehicle's owner's manual. If the fuse is blown, it means there was an overload, so you should also check for obstructions jamming the blower fan or a failing blower motor resistor.
 
How to find and check the fuse

1. Consult the owner's manual: This is the most reliable way to determine the correct fuse location and amperage for your specific vehicle. 
2. Locate the fuse box: It is usually in the cabin under the dashboard near the steering wheel, but some vehicles may have an additional fuse box in the engine bay. 
3. Identify the fuse: Look for a fuse labeled "Blower," "Heater," "HVAC," or a similar name on the fuse box diagram or in the owner's manual. 
4. Remove the fuse: Use a fuse puller or a pair of needle-nose pliers to carefully remove the fuse. 
5. Inspect the fuse: Hold the fuse up to a light to check if the metal filament inside is broken. If the metal strip is not continuous from one side to the other, the fuse is blown. 
6. Replace the fuse: If it's blown, replace it with a new fuse of the exact same amperage rating. 

This video demonstrates how to locate the heater blower motor fuse and check if it is blown: 36sCarSpyTVYouTube · Mar 14, 2025
If the new fuse blows immediately

1. Check for obstructions: Look for anything that could be jamming the blower fan, such as leaves or debris in the defroster ducts. 
2. Inspect the blower motor resistor: A failing blower motor resistor is a common cause of blown fuses, as it can draw too much current when it goes bad. 
3. Check the blower motor relay: The relay can also fail and cause the fuse to blow. 
4. Test for other issues: If these steps don't fix the problem, there may be a short in the wiring, or the blower motor itself may be failing. 

Does a car heater fan have a fuse?

Many vehicles have two fuses for the blower motor, one in the interior fuse block and the other under the hood. The blower motor is usually under the dashboard on the passenger side.

How to tell if a blower motor fuse is bad?

You can tell if a blower motor fuse is blown by visually inspecting it for a broken metal strip or cloudy/charred appearance, or by using a multimeter to check for continuity. A good fuse will show continuity (a closed circuit), while a blown fuse will have an open circuit and no continuity. If you don't have a multimeter, you can use a test light to check for power on both sides of the fuse when the ignition is on.
 
This video demonstrates how to inspect a fuse for a broken metal strip: 1mCarSpyTVYouTube · Mar 14, 2025
Visual inspection

• Locate the fuse: Find the correct fuse in your vehicle's fuse box by checking the owner's manual or the fuse box cover for a label like "Blower," "AC," or "HVAC". 
• Remove the fuse: Gently pull the fuse straight out using your fingers or a fuse puller. 
• Inspect the metal strip: Look inside the fuse for a thin metal wire that runs between the two metal prongs. If this wire is broken or missing, the fuse is blown. 
• Check for discoloration: A blown fuse may also have a cloudy or charred appearance, or a dark smudge on the small window on top. 

Using a multimeter

• Set your multimeter: Switch your multimeter to the continuity or resistance setting. A continuity test will beep if the circuit is closed. 
• Connect the probes: Touch the multimeter's probes to the metal contact points on both sides of the fuse. 
• Read the results: A good fuse will show continuity (it will beep on the continuity setting) or a very low resistance value, indicating a complete circuit. A blown fuse will show an "open" or "OL" reading, meaning there is no continuity. 

You can watch this video to learn how to test a fuse for continuity using a multimeter: 59sHVAC SchoolYouTube · Apr 19, 2021
Using a test light

• Connect the test light: Clip the test light's ground clip to a metal part of the car's chassis or the negative battery terminal. Leave the probe free. 
• Turn on the car: Turn the ignition key to the "on" position and turn on the blower fan to power the circuit. 
• Test the fuse: Touch the test light's probe to the metal part on each side of the fuse. 
• Read the results: If the test light illuminates when touching both sides of the fuse, it's good. If the light only comes on when touching one side, the fuse is blown.