2002 GMC W4500 Forward W4S042 4Cyl4.8L - Engine
My GMC W4500 turbo deisel continues to run after I have shut the key off.
In order to stop it I have to pull a cable on the left side of the engine wich turns a handle and either suts off the air supply or the fuel supply. I followed the cable to the front grill and it goes to a small sealed box with a wire harness going to it as well. I tried to take the box apart to see if it was a broken cable but couldn't open the box without seeming like I would break it. I also put a test light on the disconnected harness connecter and did not see anything live. I checked the main fuses and I found none bad. any ideas