1994 Lexus GS 300 BATTERY LIGHT AND ABS LIGHT

Hi clarence moyler,

Thank you for the donation.

Symptoms seems to indicate a failing alternator, the carbon brushes are running out or you have a bad voltage regulator.

This would result in the indicator lights showing intermittently.

Was the alternator and charging system tested when the indicator lights were showing?

The alternator could be providing charge but the voltage regulator is not reading it correctly thus the indicator light would come on.
The alternator

When the lights come on, test the voltage between the battery terminals and get the reading. If it is less than 13 volts, the charging system is not working correctly and the alternator or its carbon has to be replaced.

Test between the alternator main post and ground as well. Ensure that readings are similar for both tests, between battery terminals and between alternator and ground.

Alternatively you can remove the alternator to check the carbon brushes length.