Jump to content
  • Sign up for FREE! Become a GM-Trucks.com Member Today!

    In 20 seconds you can become part of the worlds largest and oldest community discussing General Motors, Chevrolet and GMC branded pickups, crossovers, and SUVs. From buying research to owner support, join 1.5 MILLION GM Truck Enthusiasts every month who use GM-Trucks.com as a daily part of their ownership experience. 


This topic is now archived and is closed to further replies.


Gm Upfitter Help

Recommended Posts

According to gmupfitter.com page A-67 my truck should have aux 12 volt power wiring already installed. I cant find the wire ends like it states where they are.I thinkI have found where they come from, the junction box on right end of dash.any help on where they are would be great.

heres what it states


Electrical Connections

Your vehicle is equipped with wiring provisions for a 12-volt power supply (SEO

9L4). Refer to the following information when adding electrical accessories that

will use the 9L4 12-volt power supply feeds connected to your vehicle's electrical

system. After reading the following information, keep it with your owner's manual

for future reference.

Notice: Before modifying or adding any wiring, be sure that it will

work properly with your vehicle's wiring system. Because there

are so many modifications that can be made for many different

bodies and accessories, GM cannot take responsibility for any

changes made. Such changes may not be covered by your GM

Warranty. Have the work done by an experienced electrical

technician. All wiring must be properly protected by fuses, etc.

and must be routed properly so that it will not be cut, pinched or

rubbed by other parts of the vehicle. Do not route wiring in areas

where it will be very hot. Be sure not to overload the vehicle's

wiring, connectors and components. All added wire must be at

least the same size as the wire being attached to for proper fuse


Installation Instructions —

12 Volt Accessory Power Supply

1. Disconnect the battery negative (-) cable at the battery. The

negative (-) battery cable must be disconnected before the

positive wiring lead is connected to the power accessory.

2. Locate the power supply harness under the instrument panel

near the center of the vehicle. The wire bundle consists of six

blunt cut wires, two red/white (battery hot), two black (ground),

one light green (Ign hot) and one light blue (Ign hot).

3. Remove the tape to release the wire bundles from the

power supply harness.

4. The IGN A and IGN B wires have voltage supplied and are

HOT when the ignition is turned to ACC, RUN or RAP

(Retained Accessory Power).

The BAT A and BAT B wires have direct voltage supplied

and are HOT at all times.

The combined electrical load of IGN A and BAT A must not

exceed 21 amps (250 watts). Additionally, the combined

electrical load of IGN B and BAT B must not exceed 21 amps

(250 watts). The combined electrical load of all circuits must not

exceed 42 amps (500 watts).

5. Prepare the wires that are to be used to connect the power

accessory. Do not remove the unused wires. Tape unused wires

back in their original position under the instrument panel.

6. Complete the wiring installation of the customer added

accessory with additional wire required for the specific

electrical accessory power connection. The wire gage,

12 gage (3.0 mm²), should be the same as the wiring of the

installed harness.

7. The ignition must be turned to OFF or ACC prior to attaching the

cables to the battery, or serious damage to the Vehicle Control

Module (VCM) may result.

The windshield wiper switch and the radio must be turned off

before attaching cables to the battery.

8. Reconnect the battery negative (-) cable to the battery. Torque

the bolt to 3.7 lb-ft. (5 N·m).

9. Reset the clock time and radio pushbuttons as desired

Share this post

Link to post
Share on other sites

hey guy what truck are we talking about and does it have a factory plug and hitch at the back ?

Share this post

Link to post
Share on other sites

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.