what is GEN light for on 1996 dodge ram 1500

Sounds like a charging system issue. The battery first must be recharged and checked to verify it is still good even after having been discharged fully as it has been. Once a known good battery is in place, the charging system -- alternator - can be tested to see if it is charging properly. I bet you'll find it is not -- or perhaps a belt has broken that drives the alternator. Testing is needed, followed by effective repairs. www.repairpal.com/repair-shops