Hopkins Trailer Wiring Harness Installation - 2020 GMC Sierra 1500

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How to Install a Hopkins Trailer Wiring Harness on a 2020 GMC Sierra 1500


Ryan: Hey everybody, Ryan here at etrailer.com. Today on our 2020 GMC Sierra 1500 we're going to be taking a look at and showing you how to install the Hopkins 7 and 4-Pole trailer connector socket.Since the GMC Sierra actually comes with a blank dummy plug already installed on your back bumper, it's going to make putting this one in really convenient. And since it really doesn't look any different, the back of your truck is going to look pretty much the same. I really like how versatile it is since it offers us not only a four way connector, but also a seven way. That way you should hook up to multiple different trailers that have different types of wiring.So the four way connector, that's going to provide us with our turn signals, as well as our running lights, and our brake lights. The seven way connector is going to give us those same lighting signals with a few more.

It's also going to provide us with the reverse lights, a 12 volt power for anything that might be on our trailer that needs that power, as well as an electric brake signal for pulling a trailer that has electric brakes. So it's going to be really nice having both of these plugs and one connector. For example, for pulling a smaller trailer, or maybe even using a cargo carrier that has lights, we could use our four way flat, but if you go to hookup to a larger trailer, we're going to have our seven way that we can use too.Both of the covers are going to be spring loaded, so that way whenever you're not using the plug you're not going to have to worry about any debris or anything like that getting inside potentially damaging the terminals. Now when you are using it, the seven way is going to have a keeper here, and so what that's going to do is once you plug in your trailer and close the lid, it's actually going to keep that plug in the socket and prevent it from accidentally getting pulled out.Now even though there is some rubber seals on the back of our lids to help prevent moisture from getting inside, it's never a bad idea from time to time to coat your terminals with some dielectric grease just to give them an extra layer of protection.Now since this essentially just plugs right in the installation is going to be extremely easy and shouldn't take you no time at all. Speaking of which, let's go ahead and do that together now.So here behind the bumper our connector is actually plugged into that dummy plug, so we'll need to separate the two.

So to do that there'll be a little gray tab, and you can just pull that back like so, and then you can push down on the center of it. You're able to disconnect it. And a dummy plug is held in by these little metal tabs here, you're going to have one on each side. So what you can do is just take your hand and kind of squeeze the two together and push forward, or back rather, then you're able just to work that plug right out from the bumper.Now we can grab our new plug, and this simply just pushes into that opening from which we removed our dummy plug from. Line it up, just push it flat against the bumper.

Back underneath the truck we can take our connector and plug it into our new plug. Now, before I do that what I like to do is just take some dielectric grease and kind of cover the terminals, and that'll just help keep them protected from any corrosion issues. If you need some dielectric grease, you can find it here at etrailer. Once we have it coated, line it up, plug it in, and re-secure and push down our gray tab.Now with everything connected it's a good idea to test it to make sure it's working properly. I'm using a tester box, but if you don't have one of these you can always just hook up to your trailer.

So first thing we're going to do is hit the switch and make sure that you have 12 volts back here at the plug, which we do. Now if we hop in the truck we can run through our turn signals and all of our other lighting functions. So go ahead and try out our left turn, our right turn, our brake lights, our running lights. And if you start the truck up we can put it in reverse and make sure those lights work too. And since our new plug gives us both a seven way as well as a four way, we'll go ahead and check the four way now too. So we'll try our left turn, our right turn, our brakes, and our running lights.And that'll finish up our look at and our installation of the Hopkins 7 and 4-Pole trailer connector socket on our 2020 GMC Sierra 1500.


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