Exterior Lights Circuit Description. Buick GL7 (Export) 2000

For 1990-2009 cars

### Headlamps

Battery voltage is applied to the headlamp switch continuously through CKT 2340. When the headlamp switch is in the HEAD position, voltage is applied to the headlamp dimmer switch. The headlamp dimmer switch controls the LOW beam headlamps and High beam headlamps. Battery voltage is applied to the low beam headlamps through CKT 12 when the headlamp dimmer switch is placed in the LOW position. Battery voltage is applied to the high beam headlamps and to the high beam indicator through CKT 11 when the headlamp dimmer switch is placed in the HIGH position. The headlamps are permanently grounded through G101 for the LH headlamp and G102 for the RH headlamp.

### Headlamp Position Lamps, Tail and License Lamps

Voltage is applied continuously from the PARK fuse to the headlamp and the instrument panel (IP) lamp dimmer switch through CKT 1340.

When the headlamp and the (IP) lamp dimmer switch is in the PARK or HEAD position, voltage is applied to CKT 9 thus activating the following lamps:

• | The headlamp position lamps

• | The tail lamps

• | The license lamps

All of these lamps are permanently grounded. The tailamps and the rear license lamps are grounded by G401. The headlamp position lamps are grounded by G101 for the LH lamp and G102 for the RH lamp.

### Turn Signal Lamps

When the ignition switch is the in the following positions:

• | The RUN position.

• | The BULB TEST position.

• | The START position.

Voltage is applied through the T/SIG fuse through CKT 539 to the normally closed pole of the turn switch in the turn signal switch assembly, then to the hazard lamp/turn signal flasher through CKT 1508 then back to the turn signal switch through CKT 16.

Voltage is applied from the turn signal switch through CKT 1414 and then through CKT 14 to the turn filaments of the left front park/turn lamps and LF side marker lamps, when the turn signal switch is the LEFT TURN position. Voltage is also applied through CKT 18 to the left rear turn lamp and the left turn indicator. The lamps flash ON and OFF as current flow heats up the timing element in the hazard lamp/turn signal flasher, causing it to continuously open and close the circuit. The RIGHT TURN position works in a similar way through CKT 1415 and CKT 19 to the right turn lamps.

The side marker and the turn lamps continue to flash ON and OFF, until the turn switch is turned OFF.

### Hazard Lamps

Voltage is applied continuously through the HAZARD fuse through CKT 1840 to the normally open poles of the hazard switch in the turn signal switch assembly.

When the hazard switch is ON voltage is applied to the hazard lamp/turn signal flasher through CKT 1508 then back to the turn signal switch through CKT 16, activating the following lamps to flash ON and OFF:

• | The turn lamps

• | The side marker lamps

• | Both turn indicator lamps

### Stop Lamps

Voltage is applied continuously through the STOP LAMP fuse to the stop lamp switch through CKT 140. Depressing the brake pedal applies voltage through the stop lamp switch to CKT 17, thus activating the left and the right stop lamp filaments in the tail/stop lamps and in the center high mounted stop lamp (HMSL).