replace your ign switch. its cheap-ish, and a relatively quick repair.

as for the keys and weight issue...its not that theres a weight or pressure sensor involved...its that heavy weight on the key chain accelerates wear on the ignition cylinder and ignition switch components, which in turn can lead to faster failure.

like I said, my light started coming on, at first it was just solid on every 30 or 40 trips, then it would come on every few trips, then it started doing the no-start every 20 starts or so. I could wait the time out, and restart fine. Eventually it got to the point where it would not restart after a 10 min time out, and would go through a bunch without starting (at one point I tried over 12 hours and couldnt get it started, went to bed, it started fine the next morning).

Replaced the switch, problem gone. I havnt seen the security light in a year or so

 

Hmm sounds like the next thing I need to do.

 

Could be also due to your battery starting to go bad.

 

Here is one for ya! I have a 2001 Chevy Blazer, the fuel pump went out so I replaced it. While installing the new fuel pump the battery went dead on me. So I charged it and everything seem to work great. Well I went shut the truck off and now I have this alarm that will not shut off. It acts like the key is in the ignition or the headlights are on. How can I fix this?

The Security light blinks while truck is off and have checked all doors and fuses. Nothing seems to work to shut of that alarm. HELP PLEASE