2020 Hyundai Sonata: engine overheating

Filed Sep 7, 2026 · Electrical · AR

A/C blower motor fan would stop working. Happened twice within less than a year apart. Upon further inspection, multi fuse wiring overheated and melted, ruining fuse and making A/C stop working during 100+ temperatures outside. Apparently this is a well known issue with this make and model Sonata. Electrical failure.

Filed Sep 3, 2026 · Electrical, Transmission · TX

I am submitting a safety complaint regarding a recurring, unresolved electrical defect in my 2020 Hyundai Sonata SEL. The vehicle fails to recognize when the ignition is switched off, leaving core vehicle systems active and causing severe parasitic battery drain that leaves the car immobilized. ​Description of the Problem: ​False "On" Status: After parking, turning off the engine, and exiting the vehicle, the car continues to register as though the ignition is still active/on (accessories, cluster, or vehicle network remain awake). ​ Severe Parasitic Draw: Because the vehicle fails to shut down its electrical circuits, the 12-volt battery repeatedly discharges overnight or while parked for short durations. ​Battery Replacement Did Not Resolve Issue: The 12-volt battery was replaced with a brand-new unit to eliminate typical wear, yet the drain and false "on" behavior persisted immediately. ​ Frequency: The vehicle frequently fails to start, requiring constant jump-starts or roadside assistance to operate. ​Safety Hazard: This defect creates a direct safety risk by repeatedly stranding the driver without warning in public locations, traffic stops, or remote areas. In addition, an electrical system that fails to enter a sleep state creates a potential hazard for component overheating, failure of electronic security and locking systems, or total electrical failure while attempting to restart or operate auxiliary safety equipment. Other Hyundai owners have reported identical issues where the body control modules or ignition logic fail to power down. ​Corrective Action Requested: I request that the federal safety agency investigate this electrical shutdown defect across the 2020 Hyundai Sonata model year to identify whether a faulty Body Control Module (BCM), smart key receiver, or ignition switch relay requires a safety recall and software or hardware remediation. Battery replaced on 09/04/2026 Car inspected/diagnosed by Hyundai Dealership on 09/03/2026

Filed Aug 18, 2026 · Electrical · NJ

The AC/heating blower motor circuit on my 2020 Hyundai Sonata failed intermittently due to extreme electrical resistance overheating and melting the terminal pins inside the engine fuse box. I took it to the dealership and they inspected it said it was out of warranty but it needed part number 18980-09910-FFF and wiring kit 91300L1000-FF to repair at a cost of 780.00 including parts, tax, and labor. This matches the severe design defect acknowledged in Hyundai TSB #25-EE-002H or alternative TSB-24-EEOO-1H. I filed case number 43138757 with Hyundai corporate. For now this just affects my air conditioning. However, the root failure is a known design defect that presents a severe vehicle fire hazard and potential loss of windshield defrosting capability, lights, etc. if the whole electrical system should fail. As you should know the engine bay fuse box (which currently has melted parts) is the "brain" for the car's electrical distribution. It doesn't just power my AC fan; it holds the fuses and relays for the cars fuel pump, engine control module (ECM), headlights, and electronic power steering. If left unfixed and over time as the plastic melts, copper wires will cross and touch each other, causing a massive short circuit. My engine could suddenly cut out and stall while I am traveling at 70 mph on the highway, instantly killing my power steering and power brakes and putting me in extreme danger. Again not to mention the fire hazard this situation is likely to cause. This should be addressed via a mandatory safety recall, so that I don’t have to pay for a known engineering design defect and in case the TBS bulletin fails or further unknown damage has already occurred.

Filed Nov 2, 2025 · MD

Coolant is leaking again after being fixed at a Hyundai dealer. If I don't fix it, my car will overheat and catch fire in the middle of a public road. My warranty has now expired, so I'll have to pay for the repairs myself. However, this problem is a design flaw, not related to the car's age or mileage. Hyundai should fix this problem. I'm not the only one; there are a lot of people complaining about this.

Filed Oct 15, 2025 · Electrical, Visibility · MS

Wiring harness under fuse box is not making a consistent connection and is causing the blower amp to overheat and disconnect. When this happen, cabin air doesn’t blow and the front and rear defrost stops working. The only way to make the blower engage is by removing the fuse box cover and tapping the 30 amp fuse things. I’ve taken my car to the dealership for this specific problem 5 separate times, and it was supposed to be corrected. Due to this poor connection, I am now about $1200 into repairs / replacing parts that aren’t the root cause. I am not taking my car back to the dealership for a 6th time to have it “fixed” but the service guy looked me in the face and said “you should trade it. We see this issue all the time in sonatas and elantras. It won’t be fixed”. I’ve replaced the blower motor, had the Freon charged, this is one of the vehicles with the exploding gas tank, and I’ve already paid to replace gaskets.

Filed May 26, 2024 · Electrical, Engine · AZ

Vechile shut down completely on the highway, engine's been replaced twice, Catalytic converter, Turbo was replaced three times, Battery oxygen sensors, timing belt all have been replaced, Along with my wireless charger and Both heaterhouses and splash guard. I recently had my vehicle SERVICED Thirty five hundred miles after NEW engine install The dealership serviced my car didn't reset my service indicator 3 weeks later, my vehicle without warning said Engine overheated, so I pulled over immediately that display went off. My actual thermostat stayed under the center line in between cold and hot. I contacted the dealership and got my vehicle into BE inspected At that time, they said my coolant level was low and both heapeer. Hoses needed to be replaced and my engine needed to be flushed and refilled. I had those services completed. I picked up my car 5/24 it was OK on 5/25 My service indicator pop back on and at that time it was counting 58 days, so even after I brought it to the dealership's attention, they failed to reset it again. So I googled how to reset the service interval and did it myself. And about thirty minutes later, I was driving my car started shaking excessively And Woodin's accelerate, over 20 miles per hour in traffic. I had to put on my hazard lights and get me and my grandson to a safe place so that I could contact the dealership regarding this matter and they stated there was nothing they could do I had to wait until Tuesday I have put in a complaint with the Better Business Bureau, as well as consumer affairs. And also the county attorney's office for. Consumer fraud. This vehicle was misrepresented at the time of sale. It has countless safety issues. I need assistance

Filed Dec 21, 2023 · Engine · PA

In May of 2023 my check engine light came on. Took the car to the dealer and the diagnosis was that the egr cooler was the culprit so they replaced it and everything was fine until 12/21/2023. I am driving on the highway and suddenly I hear a loud alarm and upon checking my instrument cluster I see a warning for engine overheating, the heat was on but suddenly the smell of something burning covered the entire cabin of the vehicle. I had to pull over to the side in the middle of a busy highway in freezing conditions and shut my engine down to avoid further damage. I believe the egr cooler has failed once again inly this time leading to a more terrifying experience. My car was towed to the dealership but I am worried for myself and others with similar vehicles I would not like anyone to experience what I did. I have seen multiple online forums with people complaining about the same situation. Mileage was around 57,900 miles when this occured. I bought the car with 30,000 miles as a certified preowned model. I kindly request for a recall for affected sonatas manufactured from the year 2020 to ensure our safety on the road. If it was not for warranty I would not be able to pay for the repairs