Battery light usually means alternator not charging. Most common solutions would be be a bad alternator, bad connection, or loose alternator belt. If the battery and alt test ok than check the connections to the alternator and battery.
It is usually caused by a bad alternator.
It's most likely your alternator going out, or something wrong with the charging system.....
underneath the alternator battery
If the battery light is on in your 1992 Oldsmobile Delta 88, it typically indicates an issue with the charging system. This could be due to a faulty alternator, a worn-out battery, or issues with the electrical connections. It's important to check the battery charge and the alternator's output voltage. If you're unsure, it's advisable to have a mechanic diagnose the problem to prevent potential breakdowns.
weak battery or bad alternator.
Check a for a blown/burned out fuseable link between starter and alternator
Check alternator
To replace the alternator on a 1992 SC300, first disconnect the negative battery terminal to ensure safety. Remove the serpentine belt by loosening the tensioner, then unbolt the alternator from its mounting bracket. Disconnect the electrical connectors and remove the alternator. Install the new alternator by reversing these steps, ensuring all connections are secure before reattaching the battery terminal.
Your alternator is defective. Could be the internal voltage regulator or one or more bad diodes. Replace as soon as you can to avoid getting stranded on the road.
If the battey is dead it won't charge. But it sounds like the alternator is bad. If you're sure tha battery is good then it has to be alternator, wiring, connectors or switch.
Mine had an alternator problem not putting out 14 v
alternator and od solonoid