GM Service Manual Online
For 1990-2009 cars only
Figure 1:

Cigar Lighter/Auxiliary Power Schematics - Except Sierra Denali


Object Number: 769491  Size: FS
Master Electrical Component List
Luxury Only
AIR, RTD, RADIO, RDO AMP, ECM B, FRT HVAC, and CIGAR Fuses
AUX PWR and HORN Fuses
AIR, RTD, RADIO, RDO AMP, ECM B, FRT HVAC, and CIGAR Fuses
G203 - 2 of 3 - Uplevel and Crew Cab
G203 - 2 of 3 - Uplevel and Crew Cab
G203 - 1 of 3
Figure 2:

Cigar Lighter/Auxiliary Power Schematics - Sierra Denali only


Object Number: 769497  Size: FS
Master Electrical Component List
Except Luxury
Sierral Professional Console Outlets
AIR, RTD, RADIO, RDO AMP, ECM B, FRT HVAC, and CIGAR Fuses
AUX PWR and HORN Fuses
Power, Ground and SP203
Parklamp Controls - 3 of 3
G203 - 2 of 3 - Uplevel and Crew Cab
G203 - 2 of 3 - Base Except Crew Cab
G203 - 1 of 3
Figure 3:

Sierra Professional Console Outlets


Object Number: 879164  Size: FS
Master Electrical Component List
Luxury Only
SEO 1, SEO 2, RR HVAC, EXP LPS, ATC, and RR WPR
BRAKE, Cruise, HTR A/C, RR WPR, WS WPR, and SEO ACCY Fuses
SEO 1, SEO 2, RR HVAC, EXP LPS, ATC, and RR WPR
G203 - 3 of 3
BRAKE, Cruise, HTR A/C, RR WPR, WS WPR, and SEO ACCY Fuses
G203 - 1 of 3