securtiy light blincking car wont start

Chances are you have problem with the passlock sensor. Please see the following RepairPal article for more information on GM theft systems - http://repairpal.com/gm-passlock-security-light-issues.

Hi Most of the time you will find the problem in the igntion switch key cylinder. There is a pink wire that comes from the switch that faults. Hope this helps. RJ