2010 GMC YUKON DENALI brake

Trailer Wiring Harness
Heavy-Duty Trailer Wiring Harness Package
The vehicle is equipped with the seven-wire trailer
towing harness. This harness with a seven-pin universal
trailer connector is attached to a bracket on the hitch
platform.The seven-wire harness contains the following trailer
circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed*
.Dark Blue: Trailer Brake*
*The fuses for these two circuits are installed in the
underhood electrical center, but the wires are not
connected. They should be connected by your
dealer/retailer or a qualified service center.
If charging a remote (non-vehicle) battery, press the
tow/haul mode button located at the end of the shift
lever. This will boost the vehicle system voltage and
properly charge the battery. If the trailer is too light for
tow/haul mode, turn on the headlamps as a second way
to boost the vehicle system and charge the battery.
5-59

Electric Brake Control Wiring
Provisions
These wiring provisions are included with the vehicle as
part of the trailer wiring package. These provisions are
for an electric brake controller. The instrument panel
contains blunt cut wires near the data link connector for
the trailer brake controller. The harness contains the
following wires:
.Dark Blue: Brake Signal to Trailer Connector
.Red/Black: Battery
.Light Blue/White: Brake Switch
.White: Ground
It should be installed by your dealer/retailer or a
qualified service center.
If the vehicle is equipped with an ITBC, the blunt cuts
exist, but are not connected further in the harness. If an
aftermarket trailer brake controller is installed, the ITBC
must be disconnected. Do not power both ITBC and
aftermarket controllers to control the trailer brakes at the
same time.
Trailer Recommendations
Subtract the hitch loads from the Cargo Weight Rating
(CWR). CWR is the maximum weight of the load the
vehicle can carry. It does not include the weight of the
people inside, but you can figure about 150 lbs. (68 kg)
for each passenger. The total cargo load must not be
more than the vehicles CWR.
Weigh the vehicle with the trailer attached, so the
GVWR or GAWR are not exceeded. If using a
weight-distributing hitch, weigh the vehicle without the
spring bars in place.
The best performance is obtained by correctly
spreading out the weight of the load and choosing the
correct hitch and trailer brakes.
For more information see Towing a Trailer
on
page 5‑42.
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Section 6 Service and Appearance Care
Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Accessories and Modifications . . . . . . . . . . . . . . . . . . 6-3
California Proposition 65 Warning . . . . . . . . . . . . . . . 6-4
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Doing Your Own Service Work . . . . . . . . . . . . . . . . . . 6-4
Adding Equipment to the Outside of the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Gasoline Octane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Gasoline Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
California Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Fuel E85 (85% Ethanol) . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . . 6-8
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Filling a Portable Fuel Container . . . . . . . . . . . . . . . 6-11
Checking Things Under the Hood . . . . . . . . . . . . . . .6-12
Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Engine Compartment Overview . . . . . . . . . . . . . . . . 6-14
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15
Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . 6-20
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . 6-22
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26
Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27 Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-32
Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35
Engine Fan Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35
Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36
Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . 6-37
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-38
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-41
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-42
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-47
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-48
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-49
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-50
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53
Taillamps, Turn Signal, Stoplamps and Back-up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53
License Plate Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-54
Replacement Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-54
Windshield Wiper Blade Replacement . . . . . . . . . . .6-55
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
Tire Terminology and Definitions . . . . . . . . . . . . . . . 6-61
Inflation - Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . 6-64
6-1

Service
For service and parts needs, visit your dealer/retailer.
You will receive genuine GM parts and GM-trained and
supported service people.
Genuine GM parts have one of these marks:
Accessories and Modifications
When non‐dealer/non‐retailer accessories are added to
the vehicle, they can affect vehicle performance and
safety, including such things as airbags, braking,
stability, ride and handling, emissions systems,
aerodynamics, durability, and electronic systems like
antilock brakes, traction control, and stability control.
Some of these accessories could even cause
malfunction or damage not covered by the vehicle
warranty.
Damage to vehicle components resulting from the
installation or use of non‐GM certified parts, including
control module modifications, is not covered under the
terms of the vehicle warranty and may affect remaining
warranty coverage for affected parts.
GM Accessories are designed to complement and
function with other systems on the vehicle. Your GM
dealer/retailer can accessorize the vehicle using
genuine GM Accessories. When you go to your GM
dealer/retailer and ask for GM Accessories, you will
know that GM-trained and supported service
technicians will perform the work using genuine
GM Accessories.
Also, seeAdding Equipment to Your Airbag-Equipped
Vehicle on page 2‑91.
6-3

Checking Things Under
the Hood
{WARNING:
An electric fan under the hood can start up and
injure you even when the engine is not running.
Keep hands, clothing, and tools away from any
underhood electric fan.
{WARNING:
Things that burn can get on hot engine parts and
start a fire. These include liquids like fuel, oil,
coolant, brake fluid, windshield washer and other
fluids, and plastic or rubber. You or others could
be burned. Be careful not to drop or spill things
that will burn onto a hot engine.
Hood Release
To open the hood:
1. Pull the handle withthis symbol on it. It is
located inside the
vehicle to the lower left
of the steering wheel.
6-12

A.Engine Air Cleaner/Filter on page 6‑20.
B. Coolant Surge Tank and Pressure Cap. See Cooling System on page 6‑26.
C. Remote Positive (+) Terminal. See Jump Starting
on page 6‑42.
D. Battery on page 6‑41.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
under Engine Oil on page 6‑15.
F. Automatic Transmission Dipstick (Out of View). See “Checking the Fluid Level” underAutomatic
Transmission Fluid on page 6‑22.
G. Remote Negative (−) Terminal (GND) (Out of View). See Jump Starting on page 6‑42.
H. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 6‑15.
I. Engine Cooling Fan (Out of View). See Cooling
System on page 6‑26.
J. Power Steering Fluid Reservoir (Out of View). See Power Steering Fluid on page 6‑36.
K. Brake Master Cylinder Reservoir. See “Brake
Fluid” under Brakes on page 6‑38.
L. Underhood Fuse Block on page 6‑111.
M. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on
page 6‑37.
Engine Oil
Checking Engine Oil
It is a good idea to check the engine oil level at each
fuel fill. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop.
See Engine Compartment Overview
on page 6‑14for the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes to drain back into the oil pan. If this is not done,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
6-15

Automatic Transmission Fluid
When to Check and Change Automatic
Transmission Fluid
It is usually not necessary to check the transmission
fluid level. The only reason for fluid loss is a
transmission leak or overheating the transmission.
If you suspect a small leak, then use the following
checking procedures to check the fluid level. However,
if there is a large leak, then it may be necessary to have
the vehicle towed to a dealer/retailer service department
and have it repaired before driving the vehicle further.
Notice:Use of the incorrect automatic transmission
fluid may damage the vehicle, and the damages may
not be covered by the vehicle's warranty. Always
use the automatic transmission fluid listed in
Recommended Fluids and Lubricants on page 7‑11.
Change the fluid and filter at the intervals listed in the
Maintenance Schedule. See Scheduled Maintenance
on page 7‑3. Be sure to use the transmission fluid
listed in Recommended Fluids and Lubricantson
page 7‑11.
How to Check Automatic Transmission
Fluid
Notice: Too much or too little fluid can damage your
transmission. Too much can mean that some of the
fluid could come out and fall on hot engine parts or
exhaust system parts, starting a fire. Too little fluid
could cause the transmission to overheat. Be sure
to get an accurate reading if you check your
transmission fluid.
Before checking the fluid level, prepare the vehicle as
follows:
1. Start the engine and park the vehicle on a level surface. Keep the engine running.
2. Apply the parking brake and place the shift lever in P (Park).
3. With your foot on the brake pedal, move the shift lever through each gear range, pausing for about
three seconds in each range. Then, move the shift
lever back to P (Park).
6-22

4. Allow the engine to idle (500–800 rpm) for at least
one minute. Slowly release the brake pedal.
5. Keep the engine running and press the Trip/Fuel button or trip odometer reset stem until TRANS
TEMP (Transmission Temperature) displays on the
Driver Information Center (DIC).
6. Using the TRANS TEMP reading, determine and perform the appropriate check procedure. If the
TRANS TEMP reading is not within the required
temperature ranges, allow the vehicle to cool,
or operate the vehicle until the appropriate
transmission fluid temperature is reached.
Cold Check Procedure
Use this procedure only as a reference to determine
if the transmission has enough fluid to be operated
safely until a hot check procedure can be made.
The hot check procedure is the most accurate
method to check the fluid level. Perform the hot
check procedure at the first opportunity. Use this cold check procedure to check fluid level when
the transmission temperature is between 80°F and 90°F
(27°C and 32°C).
1. Locate the
transmission dipstick at
the rear of the engine
compartment, on the
passenger side of the
vehicle.
See Engine Compartment Overview
on page 6‑14for more information.
2. Flip the handle up and then pull out the dipstick and wipe it with a clean rag or paper towel.
3. Install the dipstick by pushing it back in all the way, wait three seconds, and then pull it back out again.
4. Check both sides of the dipstick and read the lower level. Repeat the check procedure to verify the
reading.
6-23