ss502gmc

Does anyone know if you can adjust the star from behind the backing plate so i dont have to remove rotors or some way to adjust the cable?

Today i just noticed on my 01 2500hd that my tow/haul isnt coming on now. Ive never had this happen before and am curious to know if anyone has ever seen this and if so how do i fix it. I dont know the first place to look for something like this. I tried it thinking maybe the bulb burnt but it just doesnt work at all. I fo alot of heavy hauling so id like to fix this asap. Any help would be great!