GM Service Manual Online
For 1990-2009 cars only

The headlamps receive power from the HDLP circuit breaker through the headlamp switch and the turn/hazard-headlamp switch assembly. With the headlamp dimmer switch in LOW, voltage is applied to the low beam lamps via CKT 12. With the headlamp dimmer switch in HIGH, voltage is applied to the high beam lamps and the high beam indicator via CKT 11.