How to Diagnose and Fix a Blown Fuse in Your Honda Fit

How to Fix Fuse Issue

Electrical gremlins in your 2020 Honda Fit can often be traced back to a simple, yet frustrating, culprit: a blown fuse. Based on real owner experiences, the most common fuse-related problems involve circuits for accessories like interior lights, door locks, and the audio system, typically stemming from the fuse box located under the left side of the dashboard. While a fuse swap is a cheap and simple DIY fix, diagnosing the root cause of why the fuse blew is key to a permanent solution. As one owner shared about a similar experience: "To swap that fuse they would have charged me a full hour of shop time I’m sure, probably at $150/hr." — Cascadian505

Symptoms

When a fuse related to accessory circuits blows in your vehicle, the symptoms are very specific to the circuit that has lost power. You won't experience drivability issues like stalling or poor acceleration, but you will notice that certain electrical components simply stop working. The most frequently reported symptom is a complete failure of interior convenience features.

Owners most commonly report the sudden loss of interior dome lights, making it dark and inconvenient when entering the car at night. As one owner described the annoyance: "Annoying problem because I have no light when I get in the car." — Cascadian505. This is often accompanied by a non-functional radio or infotainment screen, and power door locks that refuse to operate from either the driver's switch or the key fob. In some cases, you might find that your turn signal lights or other exterior lighting have failed, though the brake lights often remain operational on a separate circuit.

A critical symptom to be aware of is the behavior of the power door locks when a specific fuse is removed or blown. One owner provided a vital warning after testing: "I removed my number 1 fuse today and the tailgate would not open nor would any other door lock or unlock. Make sure you leave the windows down so you don't accidentally get locked out of the vehicle." — Miklav05. This highlights how a single fuse can control multiple, seemingly unrelated functions like the hatch release and all power door locks. You may also encounter intermittent operation before a complete failure, which can be misleading. An owner who changed a bulb noted it "worked intermittently," suggesting an underlying electrical fault like a short circuit or moisture intrusion that eventually causes the fuse to blow completely.

Most Likely Cause

The primary cause of recurring fuse blows in the accessory circuits is a short to ground or an overload in the electrical wiring connected to that specific fuse. A fuse is a safety device; it's designed to fail first to protect the more expensive wiring and components downstream. When a wire's insulation gets damaged, often due to chafing against a metal panel or from moisture corrosion, it can create a direct path to the vehicle's chassis (a "short"). This sudden surge of current exceeds the fuse's rating, causing it to blow instantly.

Moisture is a significant enemy of automotive electrical systems and is a suspected culprit mentioned by owners. Water can seep into light housings, connectors, or wire harnesses, particularly in areas like the hatch or doors where wiring flexes with use. This moisture creates a conductive path that can lead to a short. As one owner researching a light issue speculated: "I’ve read about moisture problems which could be the cause of this." — Cascadian505. The short might not be constant—it could only occur when a door is shut, the steering wheel is turned, or during wet weather, leading to that frustrating intermittent operation before a final failure.

Another potential cause is a failing component itself drawing excessive current. For example, a small electric motor in a power window regulator or door lock actuator can begin to seize. As it struggles to move, it draws more amperage than the circuit is designed for, overheating and blowing the fuse. This is different from a direct short but has the same result. The key takeaway from owner data is that the fuse box location is consistently identified. One owner assured others: "I assure you that it is a fuse near the main fuse block under the left side dash." — Juuustpinnned. The fix starts here, but the investigation must continue to the component or wiring on that circuit.

How to Diagnose

Diagnosing a blown fuse is straightforward, but finding the root cause requires a systematic approach. You'll need the owner's manual for your 2020 Honda Fit (for the fuse box diagram), a fuse puller or a pair of needle-nose pliers, and a test light or a digital multimeter. A flashlight is essential for seeing into the dark recesses under the dashboard.

Start by locating the interior fuse box. Open the driver's door and look for a rectangular panel on the side of the dashboard, near where your left knee would be. Pry off the cover by hand; it's usually held in by plastic clips. Inside the cover or in your owner's manual, find the diagram that lists every fuse by number, its amperage rating (e.g., 10A, 15A, 20A), and the circuit it protects. Identify the fuse that corresponds to your failed component (e.g., "Door Lock," "Room" or "ACC" for interior lights, "Radio").

Visually inspect the suspect fuse. The transparent plastic body allows you to see the metal filament inside. A blown fuse will have a broken or melted filament. You can also use a test light. With the ignition in the "ON" or "ACC" position, probe both small metal tabs on top of the fuse. You should have power on both sides. If you have power on only one side, the fuse is blown. A multimeter set to continuity (the beep setting) can check the fuse while it's removed; a good fuse will show continuity (a beep), a blown fuse will not.

If the fuse is blown, replace it with a new one of the exact same amperage. Never use a higher-amp fuse, as this can cause wiring damage or a fire. Now, test the system. Do the lights or locks work? If they work immediately, operate them repeatedly and try related functions (open/close all windows, lock/unlock doors multiple times). If the new fuse blows instantly, you have a direct short. If it works for a while then blows, you have an intermittent short or a failing component. If it holds, monitor it; the problem may have been a one-time overload or may recur.

Step-by-Step Fix

This guide covers replacing a blown fuse and beginning the investigation into the underlying cause. Always disconnect the negative battery terminal before working on electrical systems if you are probing wires.

Step 1: Gather Tools and Information. Have your owner's manual, new fuses (a variety pack is ideal), a fuse puller, a test light/multimeter, and a flashlight ready. Identify the specific fuse you need to check based on the symptoms.

Step 2: Locate and Access the Fuse Box. Open the driver's door. The interior fuse box is a rectangular panel on the left side of the dashboard. Gently pry off the cover by hand. Take a moment to familiarize yourself with the layout using the diagram.

Step 3: Remove and Inspect the Suspect Fuse. Using the fuse puller tool (often found in the main under-hood fuse box or attached to the interior fuse box lid), carefully clamp onto the fuse and pull it straight out. Hold it up to the light and inspect the metal filament inside for a break. As one owner shared, the fix can be this simple, but the dealer cost is not: "To swap that fuse they would have charged me a full hour of shop time I’m sure, probably at $150/hr." — Cascadian505

Step 4: Test the Circuit (If Fuse is Blown). Before inserting a new fuse, you can do a basic test for a dead short. With the fuse removed, set your multimeter to measure resistance (Ohms). Place one probe on the load-side terminal of the fuse socket (consult the diagram on the lid to see which side is which) and the other probe on a known good ground (unpainted metal). You should see very high resistance (OL). If you see very low resistance (near 0 Ohms), there is a direct short to ground in that circuit.

Step 5: Install a New Fuse. If no immediate short is detected, insert a new fuse of the identical amperage rating. Press it firmly into place until it seats fully.

Step 6: Reconnect and Test. Reconnect the battery if you disconnected it. Turn the ignition to the "ON" position and test the previously failed component. Operate it several times.

Step 7: Investigate the Root Cause. If the fuse holds, your job may be done for now. If it blows again, you must find the short. This involves inspecting the wiring for the affected circuit. Common trouble spots are where wiring passes through door jambs or into the hatch. Look for pinched, frayed, or corroded wires. For issues with lights, check for moisture inside the housing. For door locks/windows, inspect the wiring boot between the door and the body.

Step 8: Address the Underlying Fault. If you find damaged wiring, repair it properly with solder and heat-shrink tubing, not just electrical tape. If a component is faulty (like a door lock actuator), it will need to be replaced. For complex shorts, the process may involve disconnecting components one by one to isolate the fault.

Parts and Tools Needed

• Replacement Fuses: A multi-pack of mini low-profile fuses (the type used in the interior fuse box) in various amperages (5A, 7.5A, 10A, 15A, 20A). Using the correct amperage is non-negotiable. Brand: Standard OEM or quality aftermarket like Bussmann.
• Fuse Puller: A small plastic tool designed to remove fuses without damage. Often included in fuse multi-packs or stored in the vehicle's under-hood fuse box.
• Digital Multimeter (DMM): Essential for checking fuse continuity, voltage at the fuse box, and resistance in wires to find a short. A basic model from brands like Innova or AstroAI is sufficient.
• Test Light: A simpler, quicker alternative to a multimeter for checking for power presence at the fuse box.
• Flashlight/Work Light: Crucial for seeing into the dark fuse box and under the dashboard.
• Owner’s Manual: For the official fuse box diagram and circuit descriptions specific to your 2020 Honda Fit.
• Wire Repair Supplies (if needed): Solder, heat gun, and marine-grade heat-shrink tubing for permanent wire repairs. Avoid crimp connectors for automotive wiring when possible.

Real Owner Costs

The cost to fix a fuse issue ranges from almost nothing to several hundred dollars, entirely dependent on whether you just replace the fuse or need to track down and repair a complex electrical fault.

DIY Cost (Fuse Only): This is the cheapest scenario. A pack of 50 assorted fuses costs between $5 and $10. If the fuse blew from a one-time event and replacing it fixes the problem permanently, your total cost is under $10 and 5 minutes of your time.

DIY Cost (With Component Repair): If the cause is a failed component, like a door lock actuator, the part itself might cost $50-$150. If you can install it yourself, your cost is limited to the part. One owner mentioned a related component cost: "After getting a new fuse block for the battery terminal for ~ $50..." — Juuustpinnned. This shows how component prices can vary.

Professional Repair Cost: Taking the car to a shop introduces significant labor costs. As one owner estimated for a simple fuse swap: "To swap that fuse they would have charged me a full hour of shop time I’m sure, probably at $150/hr." — Cascadian505. Even a 0.5-hour job at a $150/hr rate is $75 plus a minimal parts fee. If the problem requires diagnostic time to trace a short, you could easily be billed for 1-2 hours of labor ($150-$300) plus parts. A complex wiring repair or component replacement would be at the higher end of this range.

Prevention

Preventing fuse issues is largely about preventing the electrical faults that cause them. This involves periodic visual checks and addressing minor problems before they escalate.

Regularly inspect visible wiring, especially in high-flex areas like door jambs and the hatch. Look for cracks in the wire insulation or corrosion on connectors. When installing aftermarket accessories (dash cams, stereos, lights), always tap into power sources correctly using add-a-fuse kits and ensure all connections are soldered and insulated to prevent shorts. Keep moisture out of the vehicle by ensuring sunroof drains (if equipped) are clear and door/hatch seals are intact. If you notice a light housing filling with condensation, address the seal immediately to prevent corrosion on the bulb socket and wiring.

Finally, understand your vehicle's electrical load. While the 2020 Honda Fit's circuits are robust, constantly running high-power accessories like inverters or compressors at or near their limit can stress the system and potentially lead to overheating and fuse failure over time. Using the correct fuse is the most basic form of prevention—it's there to protect the circuit.

What Owners Say

Real experiences from HONDA owners:

Success Stories

"To swap that fuse they would have charged me a full hour of shop time I’m sure, probably at $150/hr. To be fair, I didn’t buy the car there new, but I have bought another car there once before and they have worked on this one." — Cascadian505 ($150) (source)

"To be fair, I didn’t buy the car there new, but I have bought another car there once before and they have worked on this one. Had I bought this one new I would have been pretty irate for the run around." — Cascadian505 (source)

"I’ve heard this switch can also go bad. 2) I refilled my system with 134A and my compressor started engaging but it would blow the fuse. 3) I found that the compressor clutch magnet was bad, ended up replacing that but after multiple changing out of the compressor clutch plate, I sheared off the stud on the compressor shaft (I know, not my proudest moment, should bought the special clutch holding tool). 4) replaced the compressor with a UAC branded unit, refilled and it worked." — MTLian (source)

Owner Experiences

"I also removed the plastidip from the rear diffuser, think I got tired of it. I haven't washed the car in couple of weeks, can't find the time to do it so hopefully I will do it after my nokya bulbs arrive." — cajlog (source)

"I never was a huge fan of day lights, makes the alternator use more juice. I saw a youtube video on the subject, seems all you do is take out the daylight fuse and there you go!" — GmanIV (source)

"Dear Connie, I heard some people had problems with their FOB reception. Try opening the tailgate while you have the FOB in one hand and the other hand release the tailgate while outside and behind the vehicle." — Miklav05 (source)

Lessons Learned

⚠️ "Quote: Originally Posted by SiXiam I agree you got to be careful with the harbor freight torque wrenches. Most reviews seem to have the opposite problem that you've experienced." — michel54 (source)

Pro Tips from Owners

💡 "I removed my number 1 fuse today and the tailgate would not open nor would any other door lock or unlock. Make sure you leave the windows down so you don't accidentaly get locked out of the vehicle." — Miklav05 (source)

Real Repair Costs

"Quote: Originally Posted by AirborneRATT My Dad did the exact same thing and had the exact same issue. After getting a new fuse block for the battery terminal for ~ $50, we took it to a garage which charged us half an hour to replace another fuse." — Juuustpinnned (source)

"For me I just can't spend the money on more expensive torque wrenches when I'm only maintaining one car. The one you were talking about pre-set to 18 ft-lbs is $150." — michel54 (source)

"After getting a new fuse block for the battery terminal for ~ $50, we took it to a garage which charged us half an hour to replace another fuse. I assure you that it is a fuse near the main fuse block under the left side dash." — Juuustpinnned (source)

FAQ

Q: How long does it take to replace a blown fuse? A: If you know which fuse is blown and have a replacement on hand, the actual replacement takes less than 2 minutes. Locating the correct fuse for the first time might take 5-10 minutes with the manual. Diagnosing why it blew can take anywhere from 30 minutes to several hours, depending on the complexity of the short.

Q: Can I drive my car with a blown interior fuse? A: Yes, in most cases. Blown fuses for accessories like interior lights, radio, or power door locks do not affect the core drivability of the car (engine, transmission, brakes). However, it can be a safety inconvenience (no interior light at night) or a security issue (power locks inoperative). You should address it promptly, but it typically won't strand you.

Q: Is this a common issue on the Honda Fit? A: Based on owner discussions, fuse-related electrical gremlins are a recurring topic, though not necessarily a widespread defect. The 2020 Honda Fit is generally reliable, but like any modern vehicle with complex electronics, fuses can blow due to component wear, moisture, or wiring issues. The simplicity of the fuse box under the left dash makes it a common first checkpoint for owners.

Q: Should I DIY this or take it to a mechanic? A: Replacing a known blown fuse is a perfect DIY job for any owner. It requires no technical skill beyond following a diagram. However, if you replace a fuse and it blows again immediately, or if you are uncomfortable with electrical diagnostics, taking it to a professional is wise. As one owner's experience shows, paying for diagnostic time can be worth it for elusive shorts: "After getting a new fuse block for the battery terminal for ~ $50, we took it to a garage which charged us half an hour to replace another fuse." — Juuustpinnned. They paid for expertise to find the specific fault.

Q: What does it mean if a new fuse blows instantly? A: An instant blow indicates a "hard short" or "dead short" to ground in the circuit. This means a wire has lost its insulation and is touching the metal chassis of the car, or a component has failed internally and is creating a direct path for electricity to flow to ground. This condition requires systematic diagnosis to find and repair the faulty wire or component before installing another fuse.

Q: Can a bad battery cause fuses to blow? A: Not typically. A weak or failing battery usually causes problems like slow cranking or electronic glitches due to low voltage. Fuses blow from excessive current (amperage), not low voltage. However, a failing alternator that is overcharging the electrical system (putting out more than 14.5 volts) can stress components and potentially contribute to failures that lead to a short, but it's not a direct cause of fuse failure itself.