My turn signals come on and the exterior signal lights come on as well, but they are not blinking. They just stay on. I need to get the truck inspected and I don't know where to start on this one.

 

maybe check the flasher fuse? if not the flasher fuse i had a similar issue and it turned out to be a bad taillight bulb

on my blazer. i think it's the 1157 bulb which has two elements and one was bad so it stayed on when i turned my signals on

 

I would replace the flasher first

 

on my 2004 blazer i replaced the stock front turn signals and ended up having a bulb problem where the bulb only flashed, it never stayed on, and like the 2 previous statements, it was one of the elements going bad. so it ended up only being a 5 dollar fix rather than a $50 fee at a shop for them to run tests and so forth.