GM Service Manual Online
For 1990-2009 cars only

Headlights Circuit Description Europe and Japan

When the headlamp switch is in the HEAD position, voltage is applied through the signal circuit of the headlamp switch to the headlamp dimmer switch. When the headlamp dimmer switch is in the low beam position, voltage is then applied to the left and right low beam headlamps through the supply voltage circuit of the low beam headlamps. When the voltage is applied through the supply voltage circuit of the low beam headlamps, the low beam headlamps turn on.

When the headlamp dimmer switch is moved to the high beam position, voltage is no longer applied through the supply voltage circuit of the low beam headlamps. Voltage is now applied through the supply voltage circuit of the high beam headlamps to the left and right high beam headlamps, turning them on. When the headlamp dimmer switch is in the high beam position, voltage is also applied to the instrument cluster through the supply voltage circuit of the high beam headlamps turning the IP high beam indicator on.