High Beam Operation and Flash-to-Pass

High beam operation is enabled by pulling the multi-function lever (the turn signal lever) toward the driver. The headlamp system changes state to the high beams if the low beams are already on. If the low beams are not on, and the ignition is in the RUN position, the high beams illuminate for as long as the malfunction lever is pulled and held inward (flash-to-pass position).

When the multifunction lever is pulled inward, the headlight dimmer switch closes, supplying battery positive voltage (B+) to the instrument cluster high beams/flash-to-pass input. In response to this input, the instrument cluster sends a request via the Class 2 serial data line to the PZM to activate the high beam headlamps. The PZM provides a ground for the coil of the high/low beam headlamp relay via CKT 1969 (BLK/WHT). The coil is then energized causing the switch contacts to close and apply battery positive voltage (B+) via CKT 11 (LT GRN) through the L HDLP HI fuse and R HDLP HI fuse to the left and the right headlamps respectively. The Eldorado right high beam headlamp is grounded to G101. The left high beam headlamp receives ground through the DRL relay from G101. The Deville high beam headlamps are both grounded to G101. When the switch contacts of the high/low beam headlamp relay close, battery positive voltage (B+) is removed from the low beam headlamps causing them to turn off when the high beam headlamps are on.