2010 GMC SIERRA trailer

Auxiliary Battery
The auxiliary battery provision can be used to supply
electrical power to additional equipment that may be
added, such as a slide-in camper. If the vehicle has this
provision, this relay will be located on the drivers side of
the vehicle, next to the underhood electrical center.
Be sure to follow the proper installation instructions
that are included with any electrical equipment that
is installed.
Notice:Leaving electrical equipment on
for extended periods will drain the battery.
Always turn off electrical equipment when not
in use and do not use equipment that exceeds
the maximum amperage rating for the auxiliary
battery provision.
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 5‑50.
5-77

How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer service
department.
If you do it yourself, be sure to follow all the instructions
here or you could get a false reading on the dipstick.
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.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:
.When outside temperatures are above
32°C (90°F).
.At high speed for quite a while.
.In heavy traffic —especially in hot weather.
.While pulling a trailer.
To get the right reading, the fluid should be at
normal operating temperature, which is
82°C to 93°C (180°F to 200°F). Get the vehicle warmed up by driving about
24 km (15 miles) when outside temperatures are
above 10°C (50°F). If it is colder than 10°C (50°F), drive
the vehicle in 3 (Third) until the engine temperature
gage moves and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine
run at idle for five minutes if outside temperatures are
10°C (50°F) or more. If it is colder than 10°C (50°F),
you may have to idle the engine longer. Should the fluid
level be low during this cold check, you must check the
fluid hot before adding fluid. Checking the fluid hot will
give you a more accurate reading of the fluid level.
Checking the Fluid Level
Prepare the vehicle as follows:
1. Park the vehicle on a level place. Keep the engine running.
2. With the parking brake applied, 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, position the
shift lever in P (Park).
4. Let the engine run at idle for three minutes or more.
6-24

If No Steam Is Coming From The
Engine Compartment
The ENGINE OVERHEATED STOP ENGINE or the
ENGINE OVERHEATED IDLE ENGINE message, along
with a low coolant condition, can indicate a serious
problem.
If you get an engine overheat warning, but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
.Climb a long hill on a hot day.
.Stop after high-speed driving.
.Idle for long periods in traffic.
.Tow a trailer. SeeTowing a Trailer on page 5‑50.
If you get the ENGINE OVERHEATED STOP ENGINE
or the ENGINE OVERHEATED IDLE ENGINE message
with no sign of steam, try this for a minute or so: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan speed. Open the windows as
necessary.
3. If you are stopped in a traffic jam, apply the brake, shift to N (Neutral); otherwise, shift to the highest
gear while driving —D (Drive) or 3 (Third). If the temperature overheat gage is no longer in the
overheat zone or an overheat warning no longer
displays, the vehicle can be driven. Continue to drive
the vehicle slow for about 10 minutes. Keep a safe
vehicle distance from the car in front of you. If the
warning does not come back on, continue to drive
normally.
If the warning continues, pull over, stop, and park the
vehicle right away.
If there is no sign of steam, idle the engine for
five minutes while parked. If the warning is still
displayed, turn off the engine until it cools down. Also,
see
“Overheated Engine Protection Operating Mode”
later in this section.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates firing groups
of cylinders helps prevent engine damage. In this mode,
you will notice a loss in power and engine performance.
This operating mode allows the vehicle to be driven to a
safe place in an emergency. Driving extended
miles (km) and/or towing a trailer in the overheat
protection mode should be avoided.
6-36

Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil and
reset the oil life system. See Engine Oil
on
page 6‑18.
Engine Fan Noise
If the vehicle has a clutched engine cooling fan, when
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing, and/or high outside temperatures, the fan speed
increases as the clutch more fully engages, so you may
hear an increase in fan noise. This is normal and should
not be mistaken as the transmission slipping or making
extra shifts. It is merely the cooling system functioning
properly. The fan will slow down when additional cooling
is not required and the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If the vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required. Under heavy vehicle loading, trailer towing, and/or high
outside temperatures, or if you are operating the air
conditioning system, the fans may change to high
speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system is
functioning properly. The fans will change to low speed
when additional cooling is no longer required.
Power Steering Fluid
See
Engine Compartment
Overviewon page 6‑16for reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power steering
fluid unless you suspect there is a leak in the system or
you hear an unusual noise. A fluid loss in this system
could indicate a problem. Have the system inspected
and repaired.
6-37

Underhood Fuse Block
If the vehicle has the DURAMAX®Diesel engine, see
the DURAMAX®Diesel manual for more information.
If the vehicle is a Two-mode Hybrid, see the
Two-mode Hybrid manual for more information.
The underhood fuse block is located in the engine
compartment, on the driver side of the vehicle.
Lift the cover to access the fuse block.
Notice: Spilling liquid on any electrical components
on the vehicle may damage it. Always keep the
covers on any electrical component.
To remove fuses, hold the end of the fuse between your
thumb and index finger and pull straight out.
Fuses Usage
1 Right Trailer Stop/Turn Lamp
2Electronic Suspension Control,
Automatic Level Control Exhaust
3 Left Trailer Stop/Turn Lamp
4 Engine Controls
5 Engine Control Module,
Throttle Control
6 Trailer Brake Controller
6-122

FusesUsage
7 Front Washer
8 Oxygen Sensor
9 Antilock Brakes System 2
10 Trailer Back-up Lamps 11 Driver Side Low-Beam Headlamp
12 Engine Control Module (Battery)
13 Fuel Injectors, Ignition
Coils (Right Side)
14 Transmission Control
Module (Battery)
15 Vehicle Back-up Lamps
16 Passenger Side Low-Beam Headlamp
17 Air Conditioning Compressor
18 Oxygen Sensors
19 Transmission Controls (Ignition)
20 Fuel Pump
21 Fuel System Control Module
22 Not Used
Fuses Usage
23 Not Used
24Fuel Injectors, Ignition
Coils (Left Side)
25 Trailer Park Lamps
26 Driver Side Park Lamps
27 Passenger Side Park Lamps
28 Fog Lamps
29 Horn
30 Passenger Side High-Beam
Headlamp
31 Daytime Running Lamps (DRL)
32 Driver Side High-Beam Headlamp
33 Daytime Running Lights 2
34 Sunroof
35 Key Ignition System, Theft
Deterrent System
36 Windshield Wiper
37 SEO B2 Upfitter Usage (Battery)
6-123

J-Case FusesUsage
62 Starter
63 Stud 2 (Trailer Brakes)
64 Left Bussed Electrical Center 1
65 Not Used
66 Heated Windshield Washer System
67 Transfer Case
68Stud 1 (Trailer Connector Battery
Power) (Optional - 40A Fuse
Required)
69 Mid-Bussed Electrical Center 1
70 Climate Control Blower
71 Not Used
72 Left Bussed Electrical Center 2
Relays Usage
FAN HI Cooling Fan High Speed
FAN LO Cooling Fan Low Speed
FAN CNTRL Cooling Fan Control
HDLP LO/HID Low-Beam Headlamp
FOG LAMP Front Fog Lamps
A/C CMPRSR Air Conditioning Compressor
STRTR Starter
PWR/TRN Powertrain
FUEL PMP Fuel Pump
PRK LAMP Parking Lamps
REAR DEFOG Rear Defogger
RUN/CRANK Switched Power
6-125

First Engine Oil Change After Every
80 000 km/50,000 Miles
.Engine air cleaner filter replacement. SeeEngine
Air Cleaner/Filter on page 6‑21.
.Automatic transmission fluid change (severe
service) for vehicles with Gross Vehicle Weight
Rating (GVWR) over 3 901 kg (8,600 lbs) or mainly
driven in heavy city traffic in hot weather, in hilly or
mountainous terrain, when frequently towing a
trailer, or used for taxi, police, or delivery service.
See Automatic Transmission Fluid (4-Speed
Transmission)
on page 6‑23or Automatic
Transmission Fluid (6-Speed Transmission)on
page 6‑26.
.Four‐wheel drive only: Transfer case fluid change
(severe service) for vehicles mainly driven when
frequently towing a trailer, or used for taxi, police,
or delivery service. Check vent hose at transfer
case for kinks and proper installation. Check to be
sure vent hose is unobstructed, clear, and free of
debris. During any maintenance, if a power washer is used to clean mud and dirt from the underbody,
care should be taken to not directly spray the
transfer case output seals. High pressure water
can overcome the seals and contaminate the
transfer case fluid. Contaminated fluid will
decrease the life of the transfer case and should
be replaced.
.Evaporative control system inspection. Check all
fuel and vapor lines and hoses for proper hook‐up,
routing, and condition. Check that the purge valve,
if the vehicle has one, works properly. Replace as
needed.
An Emission Control Service. The U.S.
Environmental Protection Agency or the California
Air Resources Board has determined that the
failure to perform this maintenance item will not
nullify the emission warranty or limit recall liability
prior to the completion of the vehicle's useful life.
We, however, urge that all recommended
maintenance services be performed at the
indicated intervals and the maintenance be
recorded.
7-7