when i start the blazer the lights come on, how do i turn them off?

you cant, they are daytime running lights, you are required to have them.

on your headlight panel under the circular light switch there should be a round button that turns your dome light on and off. Press it in and out 5 or more times, you should hear a ding and the lights will turn off. That works on my 2000 zr2.

just set your parking brake down about one click the daytime lights shut off...and no it doesnt hurt your brakes i leave mine set all the time to keep the lights off on both my blazer and my silverado and never had a problem in either

as for daytime running lights, this is a gm thing. at work i drive e-250s 2004-08 and they never came with daytime running lights. youre not required. its just oem to the vehicle.