Technical Description: Horn: General

The SID obtains information on the status of the horn switch from the steering wheel controls.

Fig 1: Identifying Horn Communication Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Identifying Horn Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Relay (68) for the horn is energized by the +30 circuit via fuse 17 in 342a. When the horn switch on the steering wheel is activated, the SID unit grounds pin 17, whereupon the relay operates and the horn is activated.

The horn is also used as a confirmation signal when locking the car with "TSL". In some markets the anti-theft system uses the horn, instead of a siren, as a theft alarm.

The SID receives information on the bus from TWICE commanding activation of the horn.