2007 GMC SIERRA CLASSIC Owners Manual

Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy duty trailering,
the harness is connected to the trailer mounted to
the hitch platform. The eight-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
Light Blue: CHMSL*
Red: Battery Feed**
Dark Blue: Trailer Brake
*The Center High-Mounted Stoplamp (CHMSL)
wire is tied next to the trailer wiring harness for use
with a trailer, slide-in camper or cap.
**If you are 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,
you can turn on the headlamps as a second
way to boost the vehicle system voltage and
charge the battery.
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Camper/Fifth-Wheel Trailer Wiring Package
The eight-wire camper harness is located under
the front edge of the pickup box on the driver’s
side of the vehicle, attached to the frame bracket.
A connector will have to be added to the wiring
harness which connects to the camper.
The eight-wire harness contains the following
camper/trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Light Blue: Center High-Mounted Stoplamp
(CHMSL)
Red: Battery Feed
Dark Blue: Trailer BrakeIf your vehicle is equipped with the “Heavy-Duty
Trailering” option, please refer to “Heavy-Duty
Trailer Wiring Package” earlier in this section.
When the camper-wiring harness is ordered
without the heavy-duty trailering package, an
eight-wire harness with a seven-pin connector and
separate CHMSL connector are located at the
rear of the vehicle and are tied to the vehicle’s
frame.
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Electric Brake Control Jumper
{CAUTION:
Be sure to use only the correct trailer
brake harness, the one intended for use
on your vehicle. If you use some other
trailer brake harness, even if it seems to
t, your trailer brakes may not work at all.
You could have a crash in which you or
others could be injured. Use only the
trailer brake harness intended for your
vehicle. If it is no longer available to you,
be sure to get a proper replacement from
your dealer.This harness is included with your vehicle as part
of the heavy-duty trailer wiring package.
This harness is for an electric brake controller and
includes a trailer battery feed fuse. It should be
installed by your dealer or a qualied service
center.
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Auxiliary Battery
The auxiliary battery provision can be used to
supply electrical power to additional equipment that
you may choose to add, such as a slide-in camper.
If your vehicle has this
provision, this relay will
be located on the
passenger’s side of the
vehicle, next to the
auxiliary battery.
When using this provision, connection should only
be made to the upper stud (A) of the relay. Do not
make connections to the lower stud (B) of the relay.
The auxiliary battery circuit is protected by a
megafuse located behind the auxiliary battery.
Be sure to follow the proper installation instructions
that are included with any electrical equipment
that you install.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.
Power Winches
If you wish to use a power winch on your vehicle,
only use it when your vehicle is stationary or
anchored.
Trailer Recommendations
You must subtract your hitch loads from the CWR
for your vehicle. Weigh your vehicle with the
trailer attached, so that you won’t go over
the GVWR or GAWR. If you are using a
weight-distributing hitch, weigh the vehicle without
the spring bars in place.
You’ll get the best performance if you spread out
the weight of your load the right way, and if
you choose the correct hitch and trailer brakes.
For more information, seeTowing a Trailer
on page 429.
460

Power Take-Off (PTO)
Before using a Power Take-Off (PTO), if equipped,
refer to the manufacturer’s or installer’s instructions.
To engage a PTO on a vehicle with a manual
transmission do the following:
1. Hold the clutch pedal down.
2. Set the parking brake.
3. Shift the transmission into NEUTRAL.
4. Engage the PTO. Refer to the manufacturer’s
or installer’s for instructions on electrically
engaged PTOs.
5. For mobile operations, shift the transmission
into the gear you want, apply the regular
brakes and release the parking brake.
For stationary operations, leave the parking
brake applied.
6. Release the clutch and regular brakes as you
normally would. When the clutch is released,
the PTO will start.
7. Turn the PTO rotary switch to ON.To engage a PTO on a vehicle with an automatic
transmission do the following:
1. For stationary use shift the transmission into
PARK (P).
2. Turn the PTO rotary switch ON.
3. If the engine speed is below the PTO engage
speed limit, the PTO will start. The blinking
LED on the PTO control switch indicates PTO
engage is requested. When PTO engages the
LED will switch from blinking to a steady light.
To use PTO speed control in Preset Mode (Factory
Setting) do the following:
1. Engage the PTO.
2. Select PARK (P) or NEUTRAL (N) range.
Apply the parking brake if NEUTRAL (N) is
selected. Torque Converter Clutch (TCC)
is not available in NEUTRAL (N) and is
available only in PARK (P) when engine speed
is above 1,100 rpm.
3. Make sure your foot is off the brake pedal
(and off the clutch on vehicles equipped
with a manual transmission).
4. Select the desired engine speed for PTO
operation. Read the following preset mode
information regarding operation.
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Preset Mode:PTO speed control mode is used
for stationary applications. (PTO will remain
engaged while mobile in the preset mode, however
PTO set and resume speed controls will be
inoperative.) This mode provides a default standby
speed of 800 or 850 rpm (depending on the
engine/transmission combination) and two default
PTO control speeds which follow:
1. PTO Set Speed of 1,250 rpm, or
2. PTO Resume Speed of 1,700 rpm.
Please note that the standby speed (800/850 rpm)
is not to be used as a PTO control speed.
Vehicles not equipped with cruise control will not
have the resume speed capability.
To use PTO speed control in variable mode (while
mobile) do the following:
1. Engage the PTO.
2. Vehicle speed must be greater than 5 mph.
3. Make sure your foot is off the brake pedal
(and off the clutch for vehicles equipped
with a manual transmission).
4. Select the desired engine speed by using the
foot pedal, and select SET on the PTO switch
or the cruise control.To use PTO speed control in variable mode (while
stationary) do the following:
1. Engage the PTO.
2. Vehicle speed must be less than 5 mph.
3. Make sure your foot is off the brake pedal
(and off the clutch for vehicles equipped
with a manual transmission).
4. Select the desired engine speed by using the
foot pedal, and select SET on the PTO switch
or the cruise control.
Variable Mode:PTO speed control mode can be
used for both stationary and mobile applications.
This mode allows PTO to be controlled in a fashion
similar to how cruise control sets vehicle speed.
The operator can set to an rpm (between 800 and
2,200) with the cruise control feature or with the
SET position on the PTO switch. The operator
is then able to increase rpm in increments of 100,
or “tap up” with the resume position on the
cruise control. The operator can also decrease
rpm in increments of 100 with the SET switch on
the PTO or the cruise control.
Vehicles not equipped with cruise control will not
have the “tap up” capability.
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All engine speed values listed above are factory
preset values. With the exception of the TCC
lockup speed (1,100 rpm) and the “tap” increment
(100 rpm), all of these values are programmable
and can be adjusted by your dealer or body
uptter. If the PTO software settings do not match
the settings shown here, then they may have
already been altered in order to satisfy the
requirements of the installed PTO system and
body equipment.
When the PTO switch is turned on, the engine is
limited to 2,200 rpms. If there are no accessories
installed on the vehicle, make sure the PTO switch
is turned off.Step-Bumper Pad
Your vehicle has a rear step bumper with a rear
step pad at the center of the bumper.
If you will be using the
bumper to tow a trailer,
and your step-bumper
has three cutout circles,
you must push out the
center cutout circle to
install the trailer ball.
If your step-bumper has only one cutout circle,
you will have to cut out the circle, then remove it to
install the trailer ball.
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✍NOTES
464