GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Crew) C4/C5 🢒 Accessories 🢒 Power Take-Off 🢒 Cruise Control Schematics
Figure 1:

L18/LB7/LG4/LLY
Object Number: 1464551 Size: FS
Master Electrical Component List
Cruise Control Description and Operation (6.6L and 7.8L)
Ignition Switch - RUN and ACC/RUN Bus Bars
AXLE/4WD, BRAKE, CHASSIS, and HTR/AC Fuses/Circuit Breakers
ENG 1 and ENG 4 Fuses (L18/LB7)
Figure 2:

LG5
Object Number: 795102 Size: FS
Master Electrical Component List
Cruise Control Description and Operation (8.1L)
Ignition Switch - RUN and ACC/RUN Bus Bars
AXLE/4WD, BRAKE, CHASSIS, and HTR/AC Fuses/Circuit Breakers
Device Controls - Switches