Please, I'm new with Chevy and I just got a 2000 Blazer and always has the lights on and they are not running lights because the rear ones are on too, I replaced the switch for a used one that was supposed to be good and after I turn on the engine it works perfect, on and off, turned off and 10 min later when I turned on again the lights were on again, what do you think is the problem, should I buy a brand new switch or could it be a relay or anything else that you know ? somebody please, I'll appreciate your help on this.

 

Found it, sunlight climate control sensor was bad, replaced and back to normal.