2005 GMC JIMMY trailer

5. If you have a four-wheel-drive vehicle with an
automatic transfer case, be sure the transfer case is
in a drive gear – not in NEUTRAL.
6. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in PARK (P) with the
parking brake rmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P) with
the parking brake rmly set.
If the transfer case on four-wheel drive vehicles
is in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not in
NEUTRAL.
SeeFour-Wheel Drive on page 2-30.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission uid (don’t overll),
engine oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you nd them quickly. If
you’re trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-66

Trailer Wiring Harness
The light-duty trailer wiring is a six-wire harness
assembly. The optional heavy-duty trailer wiring is an
eight-wire harness assembly. The harnesses are stored
under the vehicle, along the passenger-side frame
crossmember on two-door vehicles or on the driver’s
side corner frame rear crossmember on four-door
vehicles. The heavy-duty trailer wiring is fused in the
engine compartment fuse block. SeeFuses and Circuit
Breakers on page 5-90. Both harnesses have no
connector and should be wired by a qualied electrical
technician. The technician can use the following
color code chart when connecting the wiring harness to
your trailer.
Dark Blue: Use for electric trailer brakes or auxiliary
wiring (eight-wire harness only).
Red: Use for battery charging; it connects to the
starter solenoid (eight-wire harness only).
Light Green: Back-up lamps.
Brown: Taillamps and parking lamps.
Yellow: Driver’s side stoplamp and turn signal.
Dark Green: Passenger’s side stoplamp
and turn signal.
White: Ground wire.
Light Blue: Auxiliary stoplamp.
Securely attach the harness to the trailer, then tape or
strap it to your vehicle’s frame rail. Be sure you
leave it loose enough so the wiring doesn’t bend or
break, but not so loose that it drags on the ground. Store
the harness in its original place. Wrap the harness
together and tie it neatly so it won’t be damaged.
4-67

GM Goodwrench®oil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Do not add anything to your oil. The recommended oils
with the starburst symbol that meet GM Standard
GM6094M are all you will need for good performance
and engine protection.
When to Change Engine Oil
If any one of these is true for you, use the short trip/city
maintenance schedule:
Most trips are less than 5 miles (8 km). This is
particularly important when outside temperatures
are below freezing.
Most trips include extensive idling, such as frequent
driving in stop-and-go traffic.
You frequently tow a trailer or use a carrier on top
of your vehicle.
The vehicle is used for delivery service, police, taxi,
or other commercial application.Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and lter
every 3,000 miles (5 000 km) or 3 months — whichever
occurs rst.
If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and lter every
7,500 miles (12 500 km) or 12 months — whichever
occurs rst. Driving a vehicle with a fully warmed engine
under highway conditions will cause engine oil to
break down slower.
Remote Oil Filter (Four-Wheel Drive)
The access door for the
remote oil lter is in the
steering linkage shield
assembly located under
the radiator support.
Turn the screw to unlock
or lock the door. If you
open the door, make sure
it is securely closed
when you are nished.
5-16

Automatic Transmission Fluid
When to Check and Change
A good time to check your automatic transmission uid
level is when the engine oil is changed.
Change both the uid and lter every 15,000 miles
(25 000 km) if the vehicle is mainly driven under one or
more of these conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
service.
If you do not use your vehicle under any of these
conditions, change the uid and lter every 50,000 miles
(83 000 km).
SeePart A: Scheduled Maintenance Services on
page 6-4.
How to Check
Because this operation can be a little difficult, you may
choose to have this done at the dealership 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 uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
part or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be at
normal operating temperature, which is 180°F to 200°F
(82°C to 93°C).
5-19

If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood. Stay
away from the engine if you see or hear steam
coming from it. Just turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when your engine is
overheated, the liquids in it can catch re.
You or others could be badly burned. Stop
your engine if it overheats, and get out of the
vehicle until the engine is cool.
Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not be
covered by your warranty.
If No Steam Is Coming From
Your Engine
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. See “Driving on Grades” under
Towing a Trailer on page 4-57.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL
while stopped. If it is safe to do so, pull off the
road, shift to PARK (P) or NEUTRAL and let the
engine idle.
2. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.
5-27

6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
7. By this time, the coolant level inside the radiator
ller neck may be lower. If the level is lower, add
more of the proper DEX-COOL
®coolant mixture
through the ller neck until the level reaches
the base of the ller neck.
8. Then replace the pressure cap. At any time during
this procedure if coolant begins to ow out of the
ller neck, reinstall the pressure cap. Be sure
the arrow on the pressure cap lines up properly.
Engine Fan Noise
Your 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 clutch is not engaged. This improves fuel
economy and reduces fan noise. Under heavy vehicle
loading, trailer towing, and/or high outside temperatures,
the fan speed increases when the clutch 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 disengages.
5-33

Fuses Usage
INT BAT Instrument Panel Fuse Block Feed
ABS Anti-Lock Brake System
IGN B Column Feed, Ignition 2, 3, 4
RAP Retained Accessory Power
IGN A Starting and Charging Ignition 1
STUD #2 Accessory Feeds, Electric Brake
TRL LTRN Trailer Left Turn
Fuses Usage
LT TRN Left Turn Signal Rear
BTSIAutomatic Transmission Shift Lock
Control System
PRK LAMP Parking Lamps
HVACHeating,Ventilation, Air Cooling
System
HAZRD LP Hazard Lamps
TRL RTRN Trailer Right Turn
RT TRN Right Turn Signal Rear
TRLCHMSLTrailer Center High Mount Stop
Light
VECHMSLVehicle Center High-Mounted Stop
Lamp
TRL B/U Trailer Back Up Lamps
ECM I Engine Control Module Injectors
LDLEV Not Used
VEH B/U Vehicle Back Up Lamps
ENG IEngine Sensors/Solenoids, MAF,
CAM, PURGE, VENT
OXY SNSR Oxygen Sensor
REAR PRK Right Rear Parking Lamps
ECM BEngine Control Module, Fuel Pump
Module, Oil Pressure
5-93

Fuses Usage
B/U LAMP Back Up Lamps
IGN E Engine
L RR PRK Left Rear Parking Lamps
RR DEFOG Rear Defogger
TRL PRK Trailer Park Lamps
LT HDLP Left Headlamp
HTDMIR Heated Mirror
RT HDLP Right Headlamp
MIR/LKS Mirrors, Door Locks
ATC Transfer Case (Four-Wheel Drive)
A/C Air Conditioning
FOG LAMP Fog Lamps
TBC Truck Body Computer
RT TURN Right Turn Signal Front
CRNK Clutch Switch, NSBU Switch
LT TURN Left Turn Signal Front
FT PRK Front Parking Lamps
IGN CStarter Solenoid, Fuel Pump,
PRNDLFuses Usage
STOP LAMP Stop Lamps
HORN Horn
HTD/SEAT Heated Seat
RR W/W Rear Window Wiper
Relays Usage
STRTR Starter
REAR DEFOG Rear Defogger
FUEL PUMP Fuel Pump
HEADLAMP
PWRHeadlamp Power
DRL Daytime Running Lamps
LG Liftglass
A/C Air Conditioning
FOG LAMP Fog Lamps
HORN Horn
5-94