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Trailer Wiring Harness Installation - 2008 Chevrolet Silverado

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How to Install a Trailer Wiring Harness on a 2008 Chevrolet Silverado


Today on our 2008 Chevy Silverado Extended Cab, were going to be installing the Hopkins Universal Wiring Harness Multi-Tow Vehicle-End for Trailer Connectors part number HM40985. Before we get started here were going to go ahead and take our test light. Were going to check to make sure that the hot wire or the red wire on the rear of the vehicle is not live. To do this we will use our test light and touch the red wire on the connector. As you can see here, it still lights up which means its hot. To disconnect this well go up underneath the fuse panel under the hood.

Well remove both the 30 and the 40 amp fuse as seen here. You can remove the red wires that are just outside the fuse box on each of the two studs. Now with that done, well go ahead and double check to make sure our power has been killed. As you can see here, we no longer have a hot lead back at the old seven-pole. This particular vehicle has a work truck body on it, not the standard truck bed and someone has cut the original factory seven-pole wiring harness.

Were going to use the Hopkins Universal Wiring Harness to make some repairs. We will however have to tie two additional wires that are not standard as part of the Universal Wiring Connector. We need to do this because they are tied in with the truck body on this vehicle. In this case, were going to go ahead and tie the blue wire in with our light green wire which is the reverse light which is what they have tied in with this body and were going to add the extra green wires in with the green factory wiring as well. Were just going to double up the wires in the butt connector.

If you did not have any extra wiring here, you would just connect the butt connector straight to the factory wiring harness. Now were ready to go ahead and feed our wire in. Well connect the red with the red, the blue with the blue, the green with the green, the yellow with the yellow and the brown with the brown. The red is the power wire, the blue is the brake wire, the brown is the running, the yellow wire will be for the left turn signal and the green wire will be for the right turn signal. The purple as I said earlier is the reverse light.

In this case you go to the light green wire on the factory wiring harness and the white wire is the ground. Now because the universal wiring harness comes with a ring terminal already on the white wire which is the ground wire, were going to go ahead and add a small section of white wire to the factory wiring harness and put a ring terminal on it as well to make that be a ground. We will connect both of these ground wires to the frame using some self tapping screws. Now that we have all of our connections made, now well go ahead and reconnect the two red wires that we disconnected earlier as well as putting the two fuses back into place to make our seven-pole plug be live again. Now that weve done all the testing and everything seems to work okay, were going to go ahead and plug it into the back of our seven-way plug. On this particular vehicle theres already a seven with the four-way plug connection already on the vehicle. We just need to plug it into the back. Before we do this we use the supplied dielectric grease and put it over the connections before we plug it into the seven-pole connection. Now well go ahead and clean up our wiring underneath by taping up all the connections with electrical tape and using some zip ties to help hold the wire securely. With that that will conclude out installations of the universal wiring harness from Hopkins part number HM40985 on our 2008 Chevy Silverado.


Info for this part was:

Employee Joe V
Test Fit:
Joe V
Employee Shane T
Test Fit:
Shane T
Employee Shane H
Test Fit:
Shane H
Employee Jeff D
Installed by:
Jeff D
Employee Jacob T
Video Edited:
Jacob T
Employee Dustin K
Video Edited:
Dustin K
Employee Jonathan Y
Video by:
Jonathan Y

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