i was speeding down a tunnel and all of sudden the brake light on my custer turned on. but after i stopped it turned off. im think i do need to change but the brake but i just want sure

 

if its the light thats on when your handbrake is up check your brake fluid level.

 

cherplex is right this happened to me, as your brakes wear down the more fluid goes into the caliper which lessenes the fluid in the resivour, if its low enough when u hit the brakes the light will turn on, so add alittle, and when you do brakes remember to suck some fluid out of the resivour unless u want brake fluid to come gushing out!