Aftermarket Brake Control Wiring for 2007-2008 GM Full-Size Truck
Technical Bulletin
Summary: Wiring an aftermarket brake control to a 2007-2008 GM full-size truck Chevrolet Silverado (new body style) GMC Sierra (new body style) that has the factory Integrated Trailer Brake Control.
Problem: Installer needs new instructions (following)
Solution: When installing an aftermarket brake control into a truck that is equipped with a factory Integrated Trailer Brake Control (ITBC), you will have to make the following connections. The 2007-2008 models have four or five blunt-cut wires under the left side of the instrument panel. These wires are located above your left shin as you are seated in the driver's seat. The wires can be identified by a white label and the color of the wires. The wire colors are (1) Red/Black wire, (1) White wire, (1) Light Blue/White wire and (1) Dark Blue wire, and possibly (1) Orange wire. See Fig. 1.
Connect the brake control to these wires as follows.
- GM Wire to Brake Control Wire Function
- Red/Black to Black Battery Power
- White to White Ground
- Light Blue/White to Red Brake Light Signal
- Drk Blue N/A Brake Control Output to Trailer
- Orange N/A Center High Mount Stop Lamp (CHMSL)
Using enough 12-gauge Blue wire to reach the rear of the truck, connect one end to the Blue wire on the aftermarket brake control. Run the other end of the Blue wire in conduit or loom to the 7-way trailer connector. At the 7-way trailer connector you will have to remove some tape and pull back the plastic loom to access the factory-installed Blue wire. Cut the factory Blue wire approximately 4 to 6 inches from the trailer connector. See Fig. 2.
Connect remaining end of Blue wire from aftermarket brake control to the Blue wire going to the trailer connector. After connection is made, heat shrink, reinstall plastic loom and re-tape loom.
To complete the installation, two wires under the hood have to be connected. One is the power supply wire to the aftermarket brake control. The other is the battery charge line to the 7-way connector. These wires are both Red/Black with eyelets connected to them. They are coiled up under the hood and must be connected to the under-hood fuse box. The brake control power wire is located between the fuse box and the left (driver's side) fender. The battery charge wire is located under the master cylinder/brake booster assembly. See Fig. 3
The battery charge wire will go on the smaller Black stud, and an M6X1.0 metric nut is required to attach the wire to the stud. The brake control wire will go on the larger Silver stud along with the existing Red wire. The existing Red wire is the power wire for the factory brake control and does not need to be removed.
Important: Raising the Gray handle above the studs more than 3/8 of an inch will result in the fuse box becoming disconnected from the electrical connector.
If disconnection occurs, you may have to consult your local GM dealership for repairs.
Note: According to GM Corporate Document Number 07-08-45-001, this will not result in any trailer brake display message showing on the driver information center.
Product Number:
Manufacturer: Draw-Tite, Hidden Hitch, Reese,Tow-Ready
Bulletin Date: 02/16/08
Bulletin Number: 08-0100
Help
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Question:
I was looking for a plug on 2005 Ford explorer it has an RV plug in the back but I need to hook up a brake controller and I can not find any plug under the dash to plug in the brake controller harness.
asked by: Peter last update: June 11, 2009
Reply:
If your Explorer has the factory installed 7 way connector, it will have the connector to install the brake controller. It is located behind the center instrument cluster, to the right of the radio. You mihgt be able to reach it from underneath, but the easiest way to access it would be by removing the glove box tray.
reply by: Mike
Question:
I bought the 7 way trailer connector tester. The BK light flashes while pluged in to the truck. Is this correct. What is BK?
asked by: Jerry last update: June 9, 2009
Reply:
The 'BK' is the signal from the brake output circuit. Many brake controllers send a small amount of intermittent current through the circuit to determine if a trailer is attached. That is what is causing the light to blink.
reply by: Mike
Question:
where and how do I make the link between the 7way plug unit at the back of the truck, with the brake controler unit. I installed the controler and plugged into the port under the dash with a wireing kit, but dont know where to make the connection to run between the two. 2007 Dodge Dakota 4x4 V6 SLT extended cab truck.
asked by: Kevin last update: June 9, 2009
Reply:
What you are describing is a bit of an oddity. In my experience, the port under the dash is usually only present when the vehicle has the factory installed 7 way on the rear bumper. Take a look at our Dodge Truck Brake Controller Installation Guide. Under the heading "Factory installed 4 pole", you'll see a connector that is located behind the front wheel well on the driver's side of the truck. On the Dodge Ram trucks, this is where the brake output from the port under the dash terminates. If this is the case with your vehicle, you can tap into this wire, and run a 12 ga. wire back to the trailer connector. If this connector isn't present in your vehicle, you can simply cut the blue wire from the controller before the point where it plugs into the port under the dash, and connect it to a length of wire that runs back to the trailer connector.
reply by: Mike
Question:
I have a 2002 Honda CRV. Since I have a 2009 Aliner Scout 1100 lbs\electric brakes on order, I will need to install a 7 way harness. The Honda dealer can sell and install the harness, but does not install brake controllers. Our local CampingWorld says they can install the controller, but will not without a dealer installed harness and pigtail They claim these are two separate items. The Honda dealer does not know what the pigtail is and neither do I. What do I need besides the 7 way harness and brake controller for a 2002 Honda CRV? Any information and installation instructions would be appreciated.
asked by: Kevin last update: June 9, 2009
Reply:
I'm not aware of any pigtail that can be used for installing a brake controller on your vehicle. The CR-V is not equipped with the port under the dash for plugging in a controller, so it must be hardwired into the vehicle. We have a brake controller installation guide that will help you through the installation. As the guide mentions, in addition to the brake controller, you will need the hardwired brake controller installation kit and the T-One Vehicle Wiring Harness. This harness will tap into the CR-V's lighting circuits and will plug into the rear of the 7 way connector included in the installation kit.
reply by: Mike
Question:
2002 Ford Superduty. 7 way factory installed plug on the back. factory adaptor plug under the dash going to the controller. I cant get the trailer brakes to work, anymore. I have two trailers, and two trucks. The brakes work on the horse trailer,with the 07 Ford, for sure. But when I pluged my 02 into the same working trailer, the light on the tekonsha I thinks thats how its spelled controller doesnt show the green light, and does not turn red or orange when I step on the brake. When I put my volt meter on the brake termanal at the back of the truck, 7 way socket, I have about 10 volts. No foot on brake when I test this either. I also put my meter on the wires coming from the under dash plug, going to the controller There is 12v of power going to the controller. At first I thought it was the flat deck trailer that was the problem, but Now I think it the truck. Could the controller be the problem? Since there is power at the plug on the back, and power into the controller. How would I check to see if power comes out of the controller to the back of the truck? Everything use to work last fall, with the 02 and the horse trailer. I also checked fuses, as well as the wire conections from dash plug to controller. Im lost
asked by: Len last update: June 4, 2009
Reply:
In your question, you state that that you are getting output at the trailer connector without activating the brakes, is that correct? Can you test the blue output wire at the rear of the brake controller and see if you have power coming out on that wire without the brakes being applied? If you are getting output without the brakes being applied, the unit is bad, and must be replaced.
reply by: Mike
Question:
i just installed a activator 11 in 94 gmc Everthing seems to work except when i apply brakes with trailer on brakes apply then release with O/L message and then apply again. connected without easy connect and only using a 20 amp reset fuse instead of a 30 amp
asked by: Jason last update: June 4, 2009
Reply:
Is sounds like there is either a pinched brake circuit wire on the trailer, or the brake magnets are worn and need replacing. Pull the wheel and drum off, and look at the magnets. If you can see the copper wire showing through the face of the magnet, it needs replacement. While replacing the magnets, examine the inside of the drums where they come into contact with the magnets. If there are grooves worn in the metal, you'll want to have the inside of the drum resurfaced.
reply by: Mike
Question:
Hello, I find nothing on any van brake wiring harness applications, I have a 05 GMC Safari cargo that came with the tow package and been told I have to cut/spice wires despite the fact I have the electrical junction box like other trucks, I dont understand?
asked by: Chris last update: June 4, 2009
Reply:
Your Safari might have the junction box under the dash, but not the provision for plugging in a brake controller. GM ran a wire from the trailer connector on the bumper up to the passenger compartment. This wire is blue, and can be found near the emergency brake pedal. This wire would connect to the output (blue wire) of the brake controller. The other connections would need to be hard wired. The black wire would need to be run to te positive battery terminal, via a 20 or 30 amp circuit breaker, depending on which your brake controller requires. The white wire would ground to the negative battery terminal, and the red wire would connect to the brake stop light switch located above the brake pedal. The switch will have several wires coming out of it, use a circuit tester to locate the wire that only shows current when the brake pedal is pressed. Once you find that wire, tap the red wire into that circuit.
reply by: Mike
Question:
I have a 99 chevy 1 ton that had a 7 pin install by the previous owns mech. shop. When I hook it up to my trailor, the elec. brakes lock up right away and dont stop until I unplug it. I switched the blue and black around in the trailor connector, the trailor is a 5 pin, with and adaptor to a 7 pinand the brakes work fine now on my fathers 99 chevy. father has a later model 99, mine is the earlier 99 My question is what is right/ Also have new brake controller and the diagram that is on the installation guide looks nothing like my truck compartment.
asked by: Brian last update: June 4, 2009
Reply:
Are you using a 6 to 7 way adapter? There are two accepted ways to wire a 6 way connector. One uses the center pin as the lead for the brake output, the other uses the center pin as the 12V power supply for trailer accessories. Since you swapped those wires, and all is well, now you have no worries. Long story short, there is no one accepted way, both are correct. GM made two pickup models that year, the C/K Series, and the Silverado. That might explain why your truck looks different than the install guide.
reply by: Mike
Question:
Where would the blue wire hook up to on a 98 toyota tacoma. Is there a 6 plus harness that snaps on to such a vech? instead of running new wires from the fuse panel area?
asked by: Jay last update: June 4, 2009
Reply:
The blue wire on the trailer connector would run back to the passenger compartment and connect to the blue wire (brake output) of your brake controller. The 1998 Tacoma has no 'plug in' option for installing a brake controller. The controller would have to be directly hardwired in to the vehicle wiring. This is a fairly straightforward installation. We have a brake controller installation guide that you might find helpful. As the guide mentions, to install a controller in your vehicle, you'll need the Brake Controller Installation Kit. This kit includes everything you will need to complete your installation, even the 6 way connector. If your Tacoma doesn't have a 4 way trailer connector, you'll need a T-1 Connector that will tap into the truck's lighting circuits for the trailer to use.
reply by: Mike
Question:
I recently aquired a 1975 camper trailer that is equiped with electric brakes, however, there is what I believe to be a variable resister That is rustedtwo springs mounted parallel to each other with a double bracketthat connects the two and is adjustable to change the braking distribution between the trailer and towing vehicle Where would I find such an item or has this been replace with something new. It is a Sure Stop system????????
asked by: Lane last update: June 4, 2009
Reply:
What you are describing is a resistor. It was used to fine tune the output from the brake controller, like a limit switch. They were used because older brake controllers were not as precise as the ones produced today. If you are using a modern brake controller, it is not needed and can be disconnected.
reply by: Mike
Question:
i have a 2004 dodge diesel ram 2500 i installed a drawtite activator brake controll unit my truck had a plug in port that i used to install now My crusie control does not work right it will set and then kick off like i hit the brakes and will not work again untill i turn the truck off and start it again this does not happen all the time this will happen with or without a trailer hooked up can you give me some idea what to do to fix this problem
asked by: Tom last update: June 4, 2009
Reply:
Is this a new brake controller, or is it several years old? It sounds as if the controller is 'feeding back' to the brake switch. The only time this is supposed to happen is when the manual override switch is activated. Is it possible that the override switch is being bumped?
reply by: Mike
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