I just asked a question about my 2006 trailblazer with 48,000 miles. The service engine light does not come on when I turn the key over, neither does the seat belt light. What worries me is that I see a scuff in the dash where the screw is to remove the dash. The car hasn't given me trouble and I took it to chevrolet to have a work up done on it, and it was hooked up to a computer and no warnings came up, but WHY would that light not work? I am guessing somebody has probably tampered with it, and trying to screw me over, but its actually been a marvelous car so far. Chevrolet told me that the light is tamper proof, but I don't see how. Couldn't they just pull it out, or color it with a marker or something? I hate having the wool pulled over my eyes and it pisses me off to think someone would do that.
Tamper proof by whose terms? The average guy, maybe so. The average GM tech, maybe not. Depends if the lamp is replaceable or built into the dash assembly. Replaceable, you just get down to removing the dash assembly (no fun, usually) and pull the lamp. But as you say, Why? To go to that much trouble to hide some problem would be something a typical disreputable used car lot would pull. But on the other hand, if you've had it hooked up to a diagnostic computer and nothing shows for now, who knows if it's been tampered with or just a bad lamp. The seat belt light is another issue, unrelated to the other. Could be a simple switch bad in the retractor assembly. And if you wear the seat belt anyway, you don't really need 'reminding'.
should come on with key in the on position/have it plugged into obd and check/also go out and while its running take off the electric conn to air flow meter/that should lite it immediately
I suspect you're on the right track - it sounds as though a prior owner has removed the bulb.
the light needs to be working because the computer system will not close loop until the circuit is complete. this is true no all the rest of the computer Components. now it might act like its running fine and it might run fine for a long time. but you will not get the emission to pass if you have to have it inspected. and one of the first thing the inspectors looks at.
