Confused with this one as wiring diagrams on the web show the tan wire providing earth from the sender back to one side of the horn and the purple wire providing a positive through the ignition switch. Errr, it isn't so and the tan wire goes into what I think is the powerpack?? I think this provides a signal for limp home mode when engine get hot. Turning the ignition key on and grounding the tan wire doesn't result in the horn going off. Should it? I'm guessing the horn is in the control unit? Will there be springin', poppin' of things that are hard to put back together if i remove the cover to access it?