Roadmaster Brake-Lite Relay Kit Installation - 2016 Ford F-150

content loading

Customers compare RM-88400 to these similar products




Products Featured in this Video



How to Install the Roadmaster Brake-Lite Relay Kit on a 2016 Ford F-150


Today on our 2016 Ford F-150, we're going to be showing you how to install the Eoadmaster break light relay kit for towed vehicles. Part number is RM-88400. Now you see without our brake light relay in place, as we apply the breaks in the coach, with the blinker on, it gets very very dim and very hard to notice. That means that the brake lights in our truck are overriding the blinker signal coming from our coach. That's what our brake light relay is going to correct. Now with our brake light relay in place, we'll turn that blinker on and you'll see as we hit the brakes, they are not overridden.

We still have that full strong blinker signal, which is going to keep us both safe and legal. All right now, so here's what the relay kit is going to look like as we spread it out. Here we're going to have our actual relay, goes into a pre wired pigtail here. That's going to give us the wires we need to make our connection. Now to simplify it, white goes to the ground, red is going to go to the ignition keyed source. Now if you have turn key style ignition, you can eliminate the blue wire and you're going to follow instructions set A.

If you have a push to start type of ignition, then you'll eliminate the green wire and you'll follow instruction set B. Now we've got the turn key style here, we'll be working with today, so we're going to eliminate that blue wire, just snip it off pretty simple. Now what this is going to allow us to do is put this in line, in our brake switch. Our brake switch is on our brake peddle and it tells our brake lights when to come on. Now you saw the problem earlier, the truck's brakes are overriding the blinker from the motor home. We want to eliminate that.

By putting this in line on our break switch, the signal from our brake switch is going to have to go through our relay. It's going to come up and it wants to go out to the light. Now when our ignition is in the on position, it's going to be able to pass freely and it's going to work those brake lights, so you hit the brakes in the truck, the brake lights come on. When that ignitions off or when we have our F-150 in tow mode, it's going to stop the flow. As it stops the flow here in the relay, that's going to eliminate that problem we we're having. Now to get power we're going to tap into a fuse, basically this is going to take place of the fuse.

You'll put your original fuse there, and our new ten amp fuse is going to go in that top section. Really easy and convenient way to just get an additional power source off of that same fuse. Comes with butt connectors. It's also going to come with a ring terminal and a self-tapping screw, so we can secure our ground. However, there is a stud located underneath the dashboard there that we're going to use. That way, we can kind of eliminate drilling any extra holes. It's going to be a regular ring terminal, three-eighths inch diameter hole there. It's going to slide, be able to put our bolt right through there and then thread it in. We can eliminate these with that part. To run our power, they give us a short length. The fuse panel on the F-150 though, it's going to be over on the passenger side floor board. We're going to need about six foot of sixteen gauge wire. This is part number 16-1-1. You just want to get a quantity of six. You'll have the six foot you'll need and that should be plenty. All right now to get to that brake light switch, we're going to go in behind this panel. The switch is going to be located on the brake pedal, up there pretty high. It's kind of different to get through that way, but we'll just go in the top side here. Basically you just want to pull out on this panel and there are going to be a series of clips that hold it in place. Pop out on those, kind of tilt it down just a bit, and see we got a couple of bolts here. Before we pull those, let's get this wiring harness pulled off the backside here. It's going to be a little . Christmas tree fastener there and a little slip on fastener here. Get those popped off and then we just push in the tabs and pull out the pigtails. We'll have three of them. All right. I'll just tuck those up out of the way for now. Let's pull of these two bolts. That's going to take this panel off and also these two, so we can take off that plate. On the back side there we just squeeze those tabs together and those will slide out. Now if we come up from our brake pedal, we got this round plastic part here. We'll go just up about ten o'clock from there, hit our brake light switch, got four wires coming out. Now our sources say it's going to be the purple and white wire, but we want to verify that. To verify that we use a test light. Put it to our ground source. We just want to probe our wire there. When we hit our brake pedal now, that activates and as we release it it turns off, so we know that's going to be the right wire. Before we get into cutting or splicing this though, let's get the brake fuse removed. To get to that fuse we're going to pull that cover off. This is the passenger side kick panel, so the passenger side floor board over on the side. We want to lift right there, just pull out on that. Remove our panel. As we come in here, we need to pull fuse number fourteen, which is attached to fuse number fifteen. It's going to be a red ten amp triple fuse. Let out. Now with that fuse out, with some fabric tape around the wire loom here, let's get that heal back. Just pull that loom back and that will give us enough wire to work with there. Remember we're using our purple and white wire here. Give that wire a snip. The loom will be couple inches away from the brake light switch. Then we need to strip back both sides of it. We're going to go about twice as long as what you normally would strip on back because we're going to double our wire up. Now give that a good twist to make sure all of our wires stay together. We're going to double that over, just like that. Do the same thing for our other side here. Like that. Now to each end of that we can add one of our blue butt connectors. Now our relay kit, you can see it's pre-stripped, so pull that off, twist it up, and we'll need to trim some of that back. It's just going to be too long for the connector. Now the green wire, like we talked about, that's going to be connected to the side closest to the brake light switch here. The black side goes to the other butt connector. Now our white wire we got here, we're going to double that back as well. Add on that larger ring terminal we told you about. Now to ground that out we're going to pull out the bolt that's located right here, just to the outside of the parking brake. Uses a ten millimeter socket. If you push the parking brake down you can get a longer stroke. Now what I'm going to do is take my relay and just get it pre-positioned up here in this kind of open area. I want my ground wire to go up and over that bracket. It can come right down through the middle. We're just going to push that stud right through that ring terminal. Then we just push that bolt through that ring terminal and also this happens to be the spot we ground it out, the reed switch for our braking system as well. Just make sure we get that on there. We can secure that back down. All right, that gives us the idea of where we can mount our relay, you can see there's this wire loom right here. It's got a keeper right in front of it, so that's going to be an excellent location for us to take care of that. Now before we have it firmly mounted up there, it's a good idea to get our other wire attached here. It's going to be that additional sixteen gauge wire that we're adding in. Again, we can just use one of our butt connectors for that. Now this one we're going to be running over to the passenger kick panel. We'll just make sure we're keeping our slack over this direction. We can wrap that wherever we want, with the help of a couple zip-ties. There we're four small ones in the kit. I'm using ones that are about twice as long as that. Let's just get these wires bundled up. Got to get them a little bit nicer looking. Then we'll zip-tie these up to something solid like that wire loom. Put that right through the tab on the relay, right around that loom. All right that should keep that up and out of that way. Now to pass this from the inside to the outside under the hood, I'm going to add on a little piece of airline tubing. You can also use a coat hanger or any kind of stiffer piece of wire. Just want to get it connected. This is going to help us to push this wire through the grommet. It'd be almost impossible to do it without something a little bit stiffer than the wire itself. You see our grommet is going to be located right here. There's a hole kind of in the one-thirtyish position. That's where we'll pass through. We've already got an airline and another wire form our braking system that we previously passed through so we won't have to cut it. You just make an X shaped cut in both sides and you can pass your wires through there without any issues. Once we got that pushed through a good ways, we can go to the outside, pull it on through. All right now with my wire in the engine compartment here, I'm going to go over behind the brake booster, there. I'm going to tuck it right up behind this panel that runs across. inaudible 00:11:42 right down behind that. Now that will get me right here to my fuse box. Now there's a little lever right here on the front. Just push back on that, can lift straight up. We're going to be using this number ten fuse in the top. It will be the one, two, third fuse down from the relay bundle there. It's going to be a ten amp. Think about the length we're going to need there. Strip the end of that wire back and add it into the fuse holder. Then we can pull out the fuse we're going to use. Let that go into the bottom slot. It doesn't matter too much, they're the same ampage here. Slide our new fuse in, right above that. Then that will slide right back into its spot. Route our wire right back out of that fuse panel. Now in our cover here, where our wire passes through, we want to just reweave a small area there. Be able to pass through there without being pinched. Then we can slide our cover back on. Now that connection made, we'll slide our brake fuse back into position and we'll get that tested out. Don't forget to put your panel back in. Now to test out our relay kit, we just simply want to turn the keys on in the truck into the on position, place our foot on the brake, and see our see our lights come on. Then when we turn that ignition off, they're going to go off. That's going to indicate that we've done our job properly. Now we can get our dashboard reinstalled. All right, we're in good shape. Now with everything working properly, that's going to complete our installation of the Roadmaster brake light relay kit for towed vehicles, part number RM-88400 on our 2016 Ford F-150.


Questions and Comments about this Video

Info for this part was:

Test Fit:
Joe V
Test Fit:
Randy B
Test Fit:
Brent H
Test Fit:
Shane H
Test Fit:
Robert C
Test Fit:
David F
Test Fit:
Ryan G
Test Fit:
Clayton O
Video Edited:
Zack K
Video Edited:
Joshua S
Video Edited:
Jacob T
Video Edited:
Andrew L
Video Edited:
Dustin K
Video Edited:
Sue W
Video Edited:
Chris R
Video Edited:
Zach D
Video by:
Andrew K
Video by:
Kathleen M
Video by:
Alan C
Video by:
Jonathan Y
Video by:
Michael B
Installed by:
Cole B

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time.