I am new to the Stroke and bought me a 1994 5 speed last week and looking to put in a jake brake. Does anyone have one forsale?

Hey i just did the exhaust brake mod in my 02. I wired the switch into my brake light circut on my trailer brake switch. When i have the switch on and my foot on the brake and i turn the truck off it keeps running untill i take my foot off the brake. Not sure if this is normal or not just want...