ignition GMC SAFARI 2004 Service Manual

Then, during the rst 500 miles (800 km) that you
tow a trailer, don’t drive over 50 mph (80 km/h)
and don’t make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
See also “Driving on Grades” later in this section.
Three important considerations have to do with weight:
the weight of the trailer,
the weight of the trailer tongue
and the weight on your vehicle’s tires.
Tow/Haul Mode
Tow/haul is designed to assist while your vehicle is
pulling a large or heavy load or trailer. Tow/haul is most
useful while pulling such a load in rolling terrain, in
stop-and-go traffic, or when you need improved
low-speed control, such as when parking. The purpose
of the tow/haul mode is to:
Reduce the frequency and improve the predictability
of transmission shifts,
provide the same solid shift feel when pulling a
heavy load as when the vehicle is unloaded, and
improve control of vehicle speed while requiring less
throttle pedal activity.Press the button on the end of the shift lever to turn
tow/haul mode on and off. While activated, the indicator
light on the instrument panel will be on. Tow/haul
mode will turn off automatically when the ignition is
turned off. SeeTow/Haul Mode Light on page 3-36.
Tow/haul is most effective when the vehicle and trailer
combined weight is at least 75% of the vehicle’s
Gross Combined Weight Rating (GCWR). See “Weight
of the Trailer” later in this section.
Driving with tow/haul activated without a heavy load will
cause reduced fuel economy and unpleasant engine
and transmission driving characteristics, but will
not cause damage.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to pull
a trailer are all important. And, it can also depend
on any special equipment that you have on your vehicle.
The following chart shows how much your trailer can
weigh, based upon your vehicle model and options.
4-36

1. Check the other vehicle. It must have a 12–-volt
battery with a negative ground system.
Notice:If the other vehicle’s system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren’t touching
each other. If they are, it could cause a ground
connection you don’t want. You wouldn’t be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake rmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) and a manual
transmission in NEUTRAL.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off all
lamps that aren’t needed as well as radios. This will
avoid sparks and help save both batteries. In
addition, it could save your radio!
Notice:If you leave your radio or other accessories
on during the jump starting procedure, they could
be damaged. The repairs would not be covered
by your warranty. Always turn off your radio and
other accessories when jump starting your vehicle.4. Open the hoods and locate the batteries. Find the
positive (+) and negative (−) terminals on each
battery.
{CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing
this, and some have been blinded. Use a
ashlight if you need more light.
Be sure the battery has enough water. You do
not need to add water to the ACDelco
®battery
installed in your new vehicle. But if a battery
has ller caps, be sure the right amount of
uid is there. If it is low, add water to take care
of that rst. If you do not, explosive gas could
be present.
Battery uid contains acid that can burn you.
Do not get it on you. If you accidentally get it
in your eyes or on your skin, ush the place
with water and get medical help immediately.
5-46

Relays Usage
A/C Relay
(Rear Heat
and A/C)Rear/Heat and Air Conditioning
Uptter-ACCY
RelayUptter Accessory
Starter Enable
RelayStarter
A/C Enable
RelayAir Conditioning
Headlamps
RelayHeadlamps
Fuel Pump
RelayFuel Pump
Fuse/Circuit
BreakerUsage
UPFITTER-
BATTUptter Battery Power Stud, Trailer
Wiring Harness
UPFITTER-
ACCYUptter Accessory Relay
Spare Not used
Spare Not usedFuse/Circuit
BreakerUsage
Spare Not used
ECM-1BFuel Pump Relay and Motor, VCM,
Oil Pressure Switch/Sender
HORN Horn Relay and Horn
A/C COMPAir Conditioning Enable Relay and
Compressor
RR HTR/AC Rear Heater and Air Conditioning
ATC Active Transfer Case-L Van
FRT HVAC Front Heater and Air Conditioning
ENG-IOxygen Sensors, Camshaft Position
Sensor, Mass Air Flow Sensor,
Evaporative Emission Canister Vent
Solenoid
IGN-E Air Conditioning Enable Relay Coil
ECM-IFuel Injectors 1–6, Crankshaft
Position Sensot, VCM, Coil Driver
Module (EST), Ignition Coil
Blank Not Used
RH HDLMP Right Headlamp
LH Headlamp Left Headlamp
Blank Not Used
Blank Not Used
5-107

Fuse/Circuit
BreakerUsage
DIODE-1 Air Conditioning
Blank Not Used
Blank Not Used
Blank Not Used
LIGHTINGCourtesy Fuse, Power Adjust Mirrors
Fuse, Truck Body Control Battery
Fuse
BATTPower Accessory Circuit Breaker,
Stop/Hazard Fuse, Auxiliary Power
Fuse, Cigarette Lighter Fuse, Radio
Battery FuseFuse/Circuit
BreakerUsage
IGN A Starter Relay, Ignition Switch
IGN B Ignition Switch
ABSElectronic Brake
Control Module
Blank Not Used
RAP Radio Accessory, Power Windows
HTD MIR/RR
DEFOGRear Window Defogger,Climate
Control Head
5-108

Automatic Transmission Shift Lock
Control System Check
{CAUTION:
When you are doing this inspection, the
vehicle could move suddenly. If the vehicle
moves, you or others could be injured.
1. Before you start, be sure you have enough room
around the vehicle. It should be parked on a level
surface.
2. Firmly apply the parking brake. SeeParking Brake
on page 2-24if necessary.
Be ready to apply the regular brake immediately if
the vehicle begins to move.3. With the engine off, turn the key to the RUN
position, but do not start the engine. Without
applying the regular brake, try to move the shift
lever out of PARK (P) with normal effort. If the shift
lever moves out of PARK (P), your vehicle needs
service.Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn
the ignition key to LOCK in each shift lever position.
The key should turn to LOCK only when the
shift lever is in PARK (P).
The key should come out only in LOCK.
6-28

How to Wear Safety Belts Properly...................1-18
Hydroplaning..................................................4-18
I
If No Steam Is Coming From Your Engine..........5-30
If Steam Is Coming From Your Engine...............5-29
If the Light Is Flashing.....................................3-32
If the Light Is On Steady.................................3-32
If You Are Caught in a Blizzard.........................4-26
If You Are Stuck in Sand, Mud, Ice or Snow.......4-28
If You Do Decide To Pull A Trailer.....................4-35
Ignition Positions.............................................2-17
Ignition Transmission Lock Check......................6-28
Infants and Young Children, Restraints...............1-38
Ination - Tire Pressure...................................5-71
Inspection
Brake System.............................................6-31
Engine Cooling System................................6-30
Exhaust System..........................................6-30
Fuel System...............................................6-30
Part C - Periodic Maintenance.......................6-30
Steering, Suspension and Front Drive Axle
Boot and Seal.........................................6-30
Throttle System...........................................6-31
Transfer Case and Front Axle
(All-Wheel Drive)......................................6-31
Installing a Garage Door Opener.......................2-37Instrument Panel
Cluster.......................................................3-24
Overview..................................................... 3-2
Instrument Panel Brightness Control..................3-15
Instrument Panel Fuse Block..........................5-103
Interior Lamps................................................3-15
J
Jump Starting.................................................5-45
K
Key Lock Cylinders Service..............................6-27
Keys............................................................... 2-2
L
Lamps
Exterior......................................................3-12
Interior.......................................................3-15
Lamps On Reminder.......................................3-14
Lap Belt........................................................1-27
Lap-Shoulder Belt...................................1-18, 1-29
LATCH System
Child Restraints...........................................1-52
7