GMC TopKick 2007 Owner's Manual page 347

Fuse
STUD A Spare
STUD B Spare
Relay
LLY/L18 Fuel Pump Relay,
NOTE 1
LG4/LG5 Heated Fuel Relay
IGN B Ignition Relay
STARTER Starter Relay
HORN Horn Relay
IGN A Ignition Relay
Power Take-Off/Engine Control Unit
PTO/ECU*
(*Diesel 7.8L LG4)
REVERSE Reverse Relay
NEUTRAL Neutral Start (LG4 Allison Automatic
START Transmission Series 3000/3500)
Usage
Usage
Secondary Underhood
Fuse Block
Fuse
IGN 1 Ignition 1
IGN 4 Ignition 4
IGN 3 Ignition 3
BATT/HAZ Battery/Hazard Warning Flashers
HEADLAMP Headlamps
LIGHTING Interior/Exterior Lamps
HVAC Climate Control System
C4/C5 Electric Brake,
NOTE
C6/C7/C8 Brake Lamps
Usage
347