Cadillac Repair: electrical short, digital amp, amp meter

Question
Vehicle won't start after several days.  Needs jump-start.  Battery and alternator are ok per AutoZone.  I removed the ground cable from the battery and placed a test light on the end and attached it to the battery.  IT GLOWED.  Do I have an electrical short somewhere??  How can I narrow/diagnose the problem.

Answer
You CANNOT use a test light in this manner to test for amperage draw because the computers use a constant amperage draw of just over 1/2 amp at all times. You need to use a DIGITAL amp meter to see how many amps your vehicles system is drawing from the battery.