How Serious Is the Problem of Water Entering the Car When You Forget to Close the Windows?
3 Answers
If you forget to close the car windows during rain and water enters the car, the impact depends on the extent of water ingress. Minor water ingress: If only a small amount of rainwater enters, it won't affect the car's wiring system or mechanical system, as the wiring system is protected by covers. Simply clean and dry the wet items. Severe water ingress: Rainwater can enter the cabin, potentially causing malfunctions in electronic devices or rusting some components inside. Additionally, the front passenger area near the dashboard is prone to getting wet, which may affect electronic devices. Even if the electronics aren't damaged, the front passenger seat, floor mats, and other interior parts may still get soaked.
After that trip, I found the rear window was left open, and the heavy rain completely soaked the entire back seat. At the time, I thought just wiping it dry would be enough, but I didn’t expect the trouble that followed—water accumulated under the carpet and didn’t dry for three days, resulting in black mold spots growing inside the door panels. The worst part was that the audio wiring connectors under the back seat rusted, causing the left rear speaker to cut in and out when playing music. Now, every time I lock the car, I walk around it to double-check. I recommend that if you encounter this situation, immediately remove the seats to air them out, and ideally use a blower to blow hot air into the carpet layers. Otherwise, once mold and odors develop, it’s too late.
After a decade in auto repair, I've seen too many water-damaged cars with issues ranging from minor to severe. Rainwater itself isn't highly corrosive, but when control modules under seats or wire connectors beneath the steering wheel get soaked, real trouble begins. I once handled an SUV submerged for a week – we drained over 30 pounds of water from beneath the seat cushions, which had caused complete electrical system failure. During rainy seasons, I now advise owners to do three things immediately: disconnect the battery negative terminal, remove soaked seat cushions for sun drying, and thoroughly inspect busbar connectors under floor mats for oxidation – especially in vehicles with seat heating systems, as their control boxes are most prone to burning out.
