Speedometer short or a ghost?

[superqueso]

I think the ghost of a previous speed demon owner might haunt my '77 911S. When I turn the key and start the engine the needle jumps to 110 mph. This is either a sign to go faster or I have some sort of short. I checked the connections on the back of the speedometer and I've isolated it to an orange and black wire but I have not idea where it goes. If I disconnect the orange and black wire the needle does nothing. Does anyone know where this goes? it’s a spaghetti dinner in there. Also, my odometer and trip meter aren’t functioning either.