Diagnostic guidance. Suggested checks and possible repairs are separate from the owner's reported results.
Clarify whether the battery discharged while parked, during use or both, and provide any battery or charging-system test results already recorded.
Source: Original question and visible replies. Owner reports and other participants' experiences are distinguished. Next steps are editorial requests for clarification or existing diagnostic findings, not a verified repair procedure or an independently confirmed component diagnosis.
altenator
The owner of a 1990 Pontiac Sunbird reported continued battery discharge. A parts store reportedly found the alternator working. The starter had been replaced and wiring checked, but the discharge problem remained.
Reported outcome: No confirmed cause or successful repair of the battery-discharge problem was reported.
The reported alternator test does not establish the cause of the discharge. Battery condition, the timing of the discharge and supporting test measurements were not supplied.
