[Juergen]

For power, wire it from the battery side of the voltage regulator or from the hot side of your fuse block. The hot side of the block would make it easier for installing a fuse block or circuit breaker inside the car. You would still have to search for the BLY (Black with yellow tracer) common out of the bottom of the steering column for the ground to the relay. If you still have the old wiring where the horns should be, one of them should be hot while the other should read minimum ohms when pressing the horn button.