GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2008 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Cruise Control Schematics
Figure 1:

L18
Object Number: 1908582 Size: FS
Master Electrical Component List
Cruise Control Description and Operation (8.1L)
Control Module References
LF8/LMM
Figure 2:

LF8/LMM
Object Number: 1908586 Size: FS
Master Electrical Component List
Cruise Control Description and Operation (6.6L and 7.8L)
Control Module References
LF6
L18
Stop Lamp Switch
AXL/4WD, BRK, HYD/AIR BRK, and HTR/AC Fuses/Circuit Breakers
AXL/4WD, BRK, HYD/AIR BRK, and HTR/AC Fuses/Circuit Breakers
ENG-1 and ENG-4 Fuses - LF6/LF8
Figure 3:

LF6
Object Number: 1908591 Size: FS
Master Electrical Component List
Cruise Control Description and Operation (6.6L and 7.8L)
Control Module References
LF8/LMM
AXL/4WD, BRK, HYD/AIR BRK, and HTR/AC Fuses/Circuit Breakers
AXL/4WD, BRK, HYD/AIR BRK, and HTR/AC Fuses/Circuit Breakers
Engine Data Sensors - Low Reference 2 of 2