Good evening from Texas, the 7610 shows to use an injector in the intake manifold, it injects diesel over a glow plug like device to preheat the air in the manifold before it goes into the cylinders. It is activated by the key switch in the cold start position. I have never saw a working version as it never gets cold enough here to require it. Most have been unhooked for years. The electrical end of it opens the diesel valve and heats the glow plug as the key is held in the cold start position, which looks to be turning the key backwards from start. I will leave question in the infromation only, till you tell me different. Thank you.