1999 GMC YUKON AUX

yellowblue
4-54
Additional Heavy-Duty Wiring
An eight
-wire harness is stored under the rear bumper of
your vehicle. The five
-wire light-duty harness is located
at the left hand rear inner lower quarter panel. The
additional heavy
-duty wiring is located forward of the
rear bumper and is attached to the center of the rear
crossmember or the forward vertical surface of the
platform hitch.
This harness has a 30 amp battery feed wire and no
connector, and should be wired by a qualified electrical
technician. After choosing an aftermarket mating
connector pair, have the technician attach one connector tothe eight
-wire trailer harness and the other connector to the
wiring harness on the trailer. Be sure that the wiring
harness on the trailer is strapped to the trailer's frame and
leave it loose enough so that the wiring doesn't bend or
break, but not so loose that it drags on the ground. The
technician can use the following color code chart when
connecting the wiring harness to your trailer.

Brown: Rear Lamps

Yellow: Left Stoplamp and Turn Signal

Dark Green: Right Stoplamp and Turn Signal

White (Heavy Gauge): Ground

Light Green: Back
-up Lamps

White (Light Gauge): Center High
-Mounted Stop
Lamp (If Equipped)

Blue: Auxiliary/Electric Trailer Brake Circuit
(If Equipped)

Orange: Fused Auxiliary Circuit (If Equipped)
Store the harness in its original place. Wrap the harness
together and tie it neatly so it won't be damaged.

yellowblue
6-58
Fuse/Circuit
BreakerUsage
1 Stop/TCC Switch, Buzzer, CHMSL,
Hazard Lamps, Stoplamps
2 Transfer Case
3 Courtesy Lamps, Cargo Lamp, Glove
Box Lamp, Dome/Reading Lamps,
Vanity Mirrors, Power MirrorsFuse/Circuit
BreakerUsage
4 Instrument Cluster, DRL Relay, Lamp
Switch, Keyless Entry, Low Coolant
Module, Illuminated Entry Module
5 Rear Comfort Controls
6 Cruise Control
7 Auxiliary Power Outlet
8 Crank
9 License Lamp, Parking Lamps,
Taillamps, Tailgate Lamps, Front
Sidemarkers, Fog Lamp Relay, Door
Switch Illumination, Fender Lamps,
Headlamp Switch Illumination
10 Air Bag System
11 Wiper Motor, Washer Pump
12 A/C, A/C Blower, High Blower Relay
13 Power Amp, Rear Liftglass, Cigarette
Lighter, Door Lock Relay, Power
Lumbar Seat
14 4WD Indicator, Cluster, Front and Rear
Comfort Controls, Instrument Switches,
Radio Illumination, Chime Module

yellowblue
6-59
Fuse/Circuit
BreakerUsage
15 DRL Relay, Fog Lamp Relay
16 Front and Rear Turn Signals,
Back
-Up Lamps, BTSI Solenoid
17 Radio (Ignition)
18 4WAL/VCM, ABS, Cruise Control
19 Radio (Battery)
20 PRNDL, Automatic Transmission,
Speedometer, Check Gages,
Warning Lights
21 Security/Steering
22 Auxiliary Power, Headlamp Delay
23 Rear Wiper, Rear Washer Pump
24 Front Axle, 4WD Indicator Lamp,
TP2 Relay
A Power Door Lock, Six
-Way Power
Seat, Keyless Entry Module
B Power WindowsUnderhood Fuse/Relay Center
The underhood fuse/relay center is located in the rear of
the engine compartment near the brake fluid reservoir.
Move the retainer clips for the cover to access the
fuse block.
You can remove fuses with a fuse extractor. The fuse
extractor is mounted to the interior fuse block. To
remove fuses if you don't have a fuse extractor, hold the
end of the fuse between your thumb and index finger
and pull straight out.

yellowblue
6-60
Name Circuits Protected
ECM
-B Fuel Pump, PCM/VCM
RR DEFOG Rear Window Defogger
IGN
-E Auxiliary Fan Relay Coil, A/C
Compressor Relay, Hot Fuel Module
FUEL SOL Not Used
GLOW PLUG Not UsedName Circuits Protected
HORN Horn, Underhood Lamp
AUX FAN Auxiliary Fan
ECM
-1 Injectors, PCM/VCM
HTD ST
-FR Heated Front Seats
A/C Air Conditioning
HTD MIR Heated Outside Mirrors
ENG
-1 Ignition Switch, EGR, Canister
Purge, EVRV Idle Coast Solenoid,
Heated O
2
HTD ST-RR Heated Rear Seats
LIGHTING Headlamp and Panel Dimmer
Switch, Fog and Courtesy Fuses
BATT Battery, Fuse Block Busbar
IGN
-A Ignition Switch
IGN
-B Ignition Switch
ABS Anti
-Lock Brake Module
BLOWER Hi Blower and Rear Blower Relays
STOP/HAZ Stoplamps
HEATED
SEATSHeated Seats

9-yellowblue
9-1
Section 9 Index
A
ir Bag 1-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding Equipment 1-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How Does it Restrain 1-27 . . . . . . . . . . . . . . . . . . . . . . . . . .
How it Works 1-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Location 1-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Readiness Light 1-25, 2-73 . . . . . . . . . . . . . . . . . . . . . . . . .
Servicing 1-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What Makes it Inflate 1-27 . . . . . . . . . . . . . . . . . . . . . . . . . .
What Will You See After it Inflates 1-28 . . . . . . . . . . . . . . .
When Should it Inflate 1-27 . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner/Filter 6-15, 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner Filter Restriction Indicator Check 7-36 . . . . . . . .
Air Conditioning 3-2, 3-3, 3-4 . . . . . . . . . . . . . . . . . . . . . . . .
Air Conditioning Refrigerants 6-64 . . . . . . . . . . . . . . . . . . . . .
Alignment and Balance, Tire 6-45 . . . . . . . . . . . . . . . . . . . . . .
Aluminum Wheels, Cleaning 6-52 . . . . . . . . . . . . . . . . . . . . . .
Antenna, Fixed 3-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Antifreeze 6-23, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Anti-Lock Brake System Warning Light 2-75, 4-7 . . . . . . . . .
Anti-Lock Brakes 4-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Anti-Theft, Radio 3-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appearance Care 6-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appearance Care and Materials 6-54 . . . . . . . . . . . . . . . . . . . .
Arbitration Program 8-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ashtrays 2-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Audio Equipment, Adding 3-22 . . . . . . . . . . . . . . . . . . . . . . . .
Audio Systems 3-7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automatic Headlamp System 2
-47 . . . . . . . . . . . . . . . . . . . . . .
Automatic Transmission
Check 7
-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid 6-17, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation 2-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overdrive 2-27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Park Mechanism Check 7-38 . . . . . . . . . . . . . . . . . . . . . . . .
Shifting 2-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auxiliary Power Outlet 2-62 . . . . . . . . . . . . . . . . . . . . . . . . . .
Axle, Front 6-22, 7-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Axle, Locking Rear 2-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Axle, Rear 6-20, 7-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Battery 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jump Starting 5-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacement, Keyless Entry 2-9 . . . . . . . . . . . . . . . . . . . . .
Rundown Protection 2-50 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Warnings 5-3, 5-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BBB Auto Line 8-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Better Business Bureau Mediation 8-4 . . . . . . . . . . . . . . . . . . .
Blizzard 4-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake
Adjustment 6
-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid 6-29, 7-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Master Cylinder 6-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking 2-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pedal Travel 6-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

yellowblue
9-7
Mirrors 2-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Convex Outside 2
-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrochromic Day/Night Rearview with
Compass/Temperature Display/Headlamp Delay 2
-51 . . . . .
Electrochromic Heated Outside Rearview 2-54, 3-7 . . . . . .
Inside Rearview 2-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Remote Control 2-54 . . . . . . . . . . . . . . . . . . . . . . . . .
MMT 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model Reference vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mountain Roads 4
-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multifunction Lever 2-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Net, Convenience 2-58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Neutral, Automatic Transmission 2-26 . . . . . . . . . . . . . . . . . .
New Vehicle Break-In 2-20 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Night Vision 4-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal Maintenance Replacement Parts 6-65 . . . . . . . . . . . . .
Odometer 2-71 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Odometer, Trip 2-71 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off-Road Driving 4-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off-Road Recovery 4-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil, Engine 6-11, 6-65, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . .
OnStar
System 2-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overdrive, Automatic Transmission 2-27 . . . . . . . . . . . . . . . .
Overheating Engine 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Owner Checks and Services 7-35 . . . . . . . . . . . . . . . . . . . . . . .
Owner Publications, Ordering 8-12, 8-13 . . . . . . . . . . . . . . . .
Paint Spotting, Chemical 6-53 . . . . . . . . . . . . . . . . . . . . . . . .
Park
Automatic Transmission 2
-25 . . . . . . . . . . . . . . . . . . . . . . .
Shifting Into 2-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shifting Out of 2-35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking
At Night 2
-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake 2-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Mechanism Check 7-38 . . . . . . . . . . . . . . . . . . . . . . .
Lots 2-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over Things That Burn 2-36 . . . . . . . . . . . . . . . . . . . . . . . .
With a Trailer 4-52 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Passenger Position 1-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Passing 4-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Passlock
2-20, 2-80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Periodic Maintenance Inspections 7-39 . . . . . . . . . . . . . . . . . .
Power
Auxiliary Outlet 2
-62 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Door Locks 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lumbar Adjustment 1-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option Fuses 6-56 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Control Mirror 2-54 . . . . . . . . . . . . . . . . . . . . . . . .
Seat 1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering 4-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering Fluid 6-27, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Windows 2-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Lumbar Adjustment 1-3 . . . . . . . . . . . . . . . . . . . . . . . .
Pregnancy, Use of Safety Belts 1-22 . . . . . . . . . . . . . . . . . . . .
Problems on the Road 5-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Protecting Exterior Bright Metal Parts 6-52 . . . . . . . . . . . . . . .
Publications, Service and Owner 8-12, 8-13 . . . . . . . . . . . . . .