Dipped Beam, Halogen: Limp-home

Fig 1: Identifying Limp-Home Communication Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Identifying Limp-Home Circuit Diagram

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The limp-home function is a safety circuit in the lighting system which ensures that dipped beam can always be switched on even if DICE should be put out of action.

When the light switch is in position 2, voltage +X can also be utilized to supply the dipped-beam lamps with power. Voltage +X is fed to the dipped-beam relay, which will then be in the closed position, and the power is passed straight through the relay via the filament monitor (228b) and fuses (11 and 13) to the dipped-beam lamps. The dipped beam is somewhat dimmer, however, because the voltage drop in the system is larger than normal.