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External light warning after battery swap

Joined
Jul 17, 2025
Messages
5
After swapping out my 2017 Elantra's battery last weekend, I've seen that the external light warning icon on the dashboard won't turn off. I've gone around and checked everything, every bulb is working perfectly, including the turn signals and brake lights.

Has anyone dealt with this kind of issue after changing a battery? Do you think it just needs a reset, or could there be a more serious sensor problem? I'd really appreciate any thoughts!
 
I've run into that before on newer models after a battery change. Try disconnecting the battery again for 10 mins, reconnecting, then turning the ignition to ON without starting for about 30 secs. If it still stays lit, you may have a minor fault stored in the body control module that needs a quick scan or reset.
 
You can try the approach @Red-Research50 mentioned, but it might not be the battery. Some bulbs start to give out and not send the proper resistance and while they are on, they're failing which can cause the ECU to read it as one that's not working. That or either a socket that's corroded or damaged, which I doubt since it's not an old model. Try the battery trick and if that fails, check the bulbs or use an OBD scanner to see if there's a code. I think it might not be the battery to blame, but double check to see.
 
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