Trailer Brake Controller Installation - 2004 Chevrolet Trailblazer

Installation of a Trailer Brake Controller on a 2004 Chevrolet Trailblazer

Today on this 2004 Chevrolet Trailblazer with factory installed tow package we are going to be installing the Tekonsha P3 brake controller part number 90195. The first thing I want to note before we do our installation is what exactly the factory 7-pole looks like on the back of the Trailblazer that is going to indicate whether or not this vehicle has the wires underneath the dash to hook the brake controller into. Looking at the rear bumper area here you can see the factory installed 7-pole is kind of underneath mounted at an angle and again it is mounted to the factory hitch as well. On the lid itself there is the GM logo printed on it, that is a kind of cut and dry indicator right there as well. If you have the factory 7-pole you will have the wires under the dash to hook your brake controller to, if you do not you are likely going to have to do a manual hardwire of the brake controller and you will need to purchase some other components. 00:50

Now that we have verified that it is a vehicle that does have the factory installed tow package we need to locate the wires that we are going to be wiring the brake controller into. The wires are located in the front of the vehicle down below the steering wheel over behind the panel on the left side of the vehicle. So we are going to need to remove a few things to gain access to them. First thing there is a plastic covering here that is going to need to come down. There are two screws holding it into place, there is one right here and one located right here as well. Also mounted to this covering here is the diagnostic part and we are going to remove that as well so we can take the covering completely off. There are two screws, one on each side of the port. With those screws removed we can take the port and rotate it and feed it back out the opening in the coupling. With that removed we can pop that cover off. 01:49

With that cover pulled down, if you will look over to the left hand side attached to the main wiring lead here are the wires for our brake controller and they are taped up. What you want to do is cut the tape that is holding it into place there and separate those. From there we can take our brake controller wiring harness which is included with the P3. One end has a port on it which is going to plug into the back of the P3 and the other end has loose wires. What we are going to do is wire these directly in to the four wires on the Trailblazer and you can see that the colors are not going to match exactly so we are going to need to figure out the exact code. You can see the colors we have here on the Prodigy harness. We have got a white, a blue, a black, and a red. The white is our ground wire, the blue is our outgoing brake signal, the black is the hot lead, and the red is the connection to the brake switch. Here on our Trailblazer the only one that is going to match up is going to be the dark blues. So we are going to do dark blue to dark blue. The orange is the hot lead so we are going to hook that to the black on our harness. The light gauge black wire is the ground so that is going to go to the white. Then the light gauge light blue wire is the brake signal and that is going to go to the red on the harness. 03:06

With that indicator we can start making our connections. The controller comes with four connectors that we can use to make our connections. You can see we have got two blue ones here for the lighter gauge wires and two yellow ones for the heavier gauge wires. With those connected I am going to come over to the vehicle side and make the connections and the orange on the vehicle is going to go to the black on the harness. The dark blue is going to connect to the dark blue. The light gauge black will connect to the white. Then the light blue will connect to the red. With those connections made we can take some electrical tape and tape up those connections and then it might not be a bad idea to wrap the complete lead of cord going up to the brake controller. Now that we have got our wiring harness connected the next thing we want to do is take a look at the dash and determine where we want to mount our brake controller. A good area to mount the brake controller would be on the left or right hand side of the steering wheel itself and what we are looking for is a surface that is flat because the P3 does need to sit on a level plane and it will also need to be mounted in an area where the driver can easily access it in an emergency braking situation. On this particular vehicle we can do it on either side. For this application we are going to mount it up on the left hand side right in this area right here. If you take a look with the P3, we have two different mounting brackets that we can use. That is what we are going to determine next, which one of the brackets we would like to use. The traditional mounting bracket is a little less bulky and mounts with two screw holes that are going to mount into the dash area. The P3 is held into the bracket with the screw holes on the side. The less permanent bracket which is this one here has a small mounting bracket which is going to permanently mount to the dash area again with screw holes at the top. That is going to be held to the pocket with screws on the side and once that is mounted the P3 will clip into the pocket so there are no screws holding it into place. This is nice if you want to remove it when you are not using it or if you are going to be using the controller between a couple of different vehicles. Again for this application this is the bracket that we are going to be using. 06:00

So I can separate these two pieces and determine where we are going to mount it again. I think right in this area is going to be a nice spot so from there we are going to take a couple of self tapping screws that are provided with the kit and mount it into position. Before I put the second screw in again I just want to double check and make sure that the mounting bracket is in a straight line with the braking of the vehicle. We do not want the bracket to be mounted side to side at all because then the brake controller will not perform properly. From there we are going to take our second portion of our bracket and mount these two together. We are going to be taking again the self tapping screws that are provided with the kit and make the connection between the two. What I am going to do prior to merging the two is take the self tapping screw and run it in and out a few times because we are going to need to form the threads into the bracket and that is going to make it easier when we go to merge the two. Then I can take the two and mount them together. With the bracket mounted we are going to come back to the wiring harness now and we just want to determine not only how we are going to route the harness up but how much of the length we are actually going to need. On this plastic covering since it is going back into position we are going to need to find a way to get the harness out up to the bracket. There is a nice large hole here that we can take and route the wires through. Just feed that up to the brake controller area and we are next going to take our P3 and plug the harness into it and you can see we instantly get a read out on the controller telling us that we do not have a trailer connected. We can it into the mounting bracket and again there are no screws needed here. Put the back end into the back of the pocket, rotate it up and where the mounting holes are at on the side, those are going to clip into the bracket and hold it in place. Then I am going to come back down to the excess wires here and take some zip ties and hide the wires up behind the dash area and from there we need to put our covering back on and our installation will be complete. With that, that will conclude the installation of the Tekonsha P3 brake controller part number 90195 on a 2004 Chevrolet Trailblazer.