 Turns out this spastic turn signal, or blinker, as we tend to call them here in Wisconsin, was due to one of the lights just being burned out. Seems simple enough. Then I YouTubed how to fix it, and sure enough, there were multiple videos explaining how to fix a burned out blinker on my exact make, model, and year of truck. I admit, being the novice that I am, I probably watched that video a dozen times.