etrailer | Install: Roadmaster Brake-Lite Relay Kit for Towed Vehicles on a 2018 Ford F-150

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Full transcript: https://www.etrailer.com/tv-install-r...
Speaker 1: Today on our 2018 Ford F150, we're going to be taking a look at and showing you how to install the Roadmaster Brake-Lite relay kit for towed vehicles, part number RM-88400. First let's talk about what comes in our kit. You're going to have your brake relay, which is going to attach to your brake light switch, your fuse tap, your 10 amp fuse, a few butt connectors, ring terminal, your self tapping screw, and a little extra wire.So let's talk about what our vehicle's going to do if we don't have our brake relay installed. Let's say you have a brake system on your towed vehicle or on your Ford. You're towing it down the road, when you hit your brakes in your RV, the brake lights are going to come on in your truck or in your towed vehicle. However, when you hit your brakes and you turn on your blinker in your RV, you're only going to see the brake lights in the truck because the brake light signal is overriding that turn signal.

What this relay is going to do, it's going to allow that signal to transfer from the RV to the truck. When the key's in the on position, that circuit will close to allow you to use all the proper functions in the truck by their self. When the key is turned off, that's going to allow the signal from the RV, your blinkers, and your brakes to function properly in your towed vehicle.Now if you have a push button start, you'll use the blue wire. If you have a key ignition, you'll use the green wire. So what we're going to do is we're going to eliminate our blue wire.

We'll just cut that off. Your black wire's going to run to your brake light signal. Red wire's going to run out to your fuse. Green wire is going to run to your brake light switch and your white wire is going to be the ground. So if you have a turn key ignition, you're going to use section A of your instructions.

If you have a push button start, you're going to use section B of your instructions.Couple of things you're going to need. This wire, red wire is not going to be long enough to get to your fuse because it's all the way in the passenger side of the engine compartment. So you're going to need to pick about six foot of wire and you can find that on our website using part number 16-1-1. Another thing you're going to need, is you're going to need a volt meter. And that's to test your wire from your brake switch.Let's talk about why you need a volt meter over just a regular test light.

You're going to have multiple wires going into your brake light switch. If you test those wires, you're going to have several of them that are going to make that light, light up. However, you're not going to know which one you need to tap into. The brake light switch or wire that you're going to be tapping into, is the only wire that's going to read 12 volts. All the other ones will not.Another thing I like to have is maybe an extra ring terminal, a little bit larger. Just in case we find a stud on the firewall or somewhere that we can tie into that we don't have to actually bolt in or screw into the metal itself. So what we need to do is on our driver's side, we need to take this panel off. All we're going to do is pull back on it. It's going to be attached by a few clips. Just like that, we'll fold it down. If you look right here, you're going to have a couple wiring harnesses. We need to unplug those and we're going to take them and we're going to tuck them right up here out of the way for now. So next we're going take a 10 millimeter socket. We're going to take out these two screws and a bolt. Then we're going to take out the top two on this metal panel.Remove that panel. And then right on the back side, you're going to have two push clips that hold this in place. And we're just going to push them together and slide them out. Then we're going to take this panel, set it aside. So we're looking for this light blue switch right here. The wires that are coming off the back of it, we need to take this coating off or this tape. So we'll just start peeling it off. You want to peel it back pretty far. Then what we need to do is test our wires to figure out which one is going to give us that 12 volt power when the brakes are applied. We should only have one. We'll start with the one all the way on the left. With an extra set of hands, we'll have somebody push on the brake pedal. And I think that's going to be our wire