99 Astro security no start

My 99 Astro was having a problem where it would not start occasionally. The security light has been on intermittently. I brought it to my mechanic and he said the wiring inside the dash is no good. Before I tear apart the dash of the parts van, is there any way to bypass the security to be sure this is the problem? It is now not starting at all since messing with the wiring. Ignition module has been changed. I would greatly appreciate any help!