I have a 2000 silverado 4x4 5.3 and here's the problem I'm having.
When the truck is running and the headlights are on if I turn the heater to high, the led gear select light (the light that surrounds the gear it's in) starts to flicker on and off then stays off and a few seconds later, the security light comes on. If I turn the headlights off or turn the heater to a lower speed even the gear select light comes on and the security light goes off. The truck runs fine with the light on or off but it's been doing it for a couple months now and it's bugging the heck outta me. I tried hooking my atap to it to check if the computer is pulling any codes and it hasn't. I also checked the voltage thinking it might have something to do with it considering it does it seemingly when the electrical system is under a heavy load but it shows 14.0/14.1 volts while running.

The dealer wants 80 bucks just to look at it so I figured to try here first.

Any suggestions??

 

man i hate to say it but that sounds like a ground wire problem. where to start im not sure. have you had the dash apart lately?

 

No, the dash has never been apart. I was also thinking a short somewhere but where to start looking has me

 

hey does it do it more when the lights are on. or at anytime.

 

When the headlights are on it does it all the time. When they're off it rarely does it.

 

did you mess with the wires under the hood?

 

No, the truck is completly stock and untouched from the factory.