What does it mean when the plus and minus signs on the car dashboard light up?
2 Answers
When the plus and minus signs on the car dashboard light up, it indicates that the generator's output voltage is lower than the battery voltage, the generator is not working, or there is a fault in the power supply circuit. The reasons for the charging system warning light to illuminate are as follows: If the light remains on after the car is started: It indicates that the generator's output voltage is lower than the battery voltage, the generator is not working, or there is a fault in the power supply circuit. In this case, the vehicle is running on battery power, and you should take it to a repair shop as soon as possible to inspect the generator and charging circuit. If the battery is not charging, it will run out of power: Like all batteries, if not charged, the car's 12-volt battery will eventually run out of power, which is why cars have a built-in charging system.
I've been driving for almost twenty years and have encountered that battery light with the plus and minus sign on the dashboard several times. The technical name for it is the charging system warning light, which basically means the alternator isn't charging the battery. The most common cause is a loose or broken alternator belt—last time it happened to me on the highway, I immediately turned off the AC and radio to save power and barely made it to a service area. If the alternator itself fails, it's even worse because unstable voltage can make the dashboard go haywire. Loose battery terminals or aging wiring can also trigger this light. My advice is to immediately find a safe place to turn off the engine and check the belt tension, or use a multimeter to measure the battery voltage. Never keep driving stubbornly, or you might end up stranded and needing a tow truck, which wastes both time and money.
