Both front and rear turn signals will not blink. All signal lights come on but stay on including panel signal lights inside. Just no blinking. I replaced signal flasher on rear of fuse panel still does not blink.
I had this problem recently. It was the turn signal relay/fuse thing. It's silver and round in the fuse panel. On my 92, one controlled both sides. There's another one on the back side that I assume is for the caution lights.
Most trucks have the flasher replaced with a heavy duty one so trailers don't mess with the blinker timing, so it wouldn't necessarily blink faster or slower. But when a flasher fails completely it just doesn't flash.