Backup lights on trailer

[SouthwestOregon201]

For those who have installed backup lights on your FGRV, have you had to modify the wiring system with any relay device since the extended wiring from your tow vehicle may not work?

I am going to install a new 7 pin harness and was wondering if I can just add the extra 10 feet of wiring and put on backup lights on the rear bumper of the trailer.

Dave Heffner
Roseburg, OR

[David B.]

Dave, that's the same thing I was wanting to do, so I will be anxiously awaiting the experts responses. I would think that if you used LED back-up lights, you should be fine without a relay. These are what I was planning on using, only 220mA.
http://www.superbrightleds.com/morei...uct/1251/1979/
Good Luck
Dave & Paula

[Jim Bennett]

You can use the center connection for backup lights. It is not used for the trailer lights, or the 12V power. You would just have to run a wire from the end of the trailer pigtail to the light location. As well, it is likely you may have to connect from the vehicle backup circuit to the connector too.

[Carol H]

Originally Posted by Jim Bennett

You can use the center connection for backup lights. It is not used for the trailer lights, or the 12V power. .

That depends on how the trailer & tug are wired. My truck came wired using the Heavy Duty Truck 7 way wiring code so the electric brakes are using the centre pin. That matches up with how the Scamp is wired as well so it was a simple plug and play.

E-Trailer has good Diagrams of the 3 different possible configurations for a 7 pin connection.

[floyd]

If you want the backup lights to perform as a signal to other drivers that you are backing up then you can go the conventional route. You can buy RV taillights with the backup lights built in. my scamp had them from the factory.

If you want backup lights for the purpose of seeing your camp site when backing in, then youmight try this...

place one or two small driving lights facing straight down behind your rear bumper.
wire them from your battery through a switch and out to the trailer.
This will light up the area beautifully and you can even see your tires and all the area around and on both sides.
This could even be done without the the tow vehicle being involved by wiring them to the trailer battery with an onboard switch. if you use LED backup lights then you could even use them as a homing beacon on your trailer when you leave your campsite at night.

[Jim Bennett]

Originally Posted by Carol H

That depends on how the trailer & tug are wired. My truck came wired using the Heavy Duty Truck 7 way wiring code so the electric brakes are using the centre pin. That matches up with how the Scamp is wired as well so it was a simple plug and play.

E-Trailer has good Diagrams of the 3 different possible configurations for a 7 pin connection.

This is the standard wiring from your link which is what I have in my Ford F-350, and my Honda Pilot, and what I am used to, though have lead a sheltered life. I have never seen anything different in what I have owned or worked on. I have never seen other than the blue used for brakes. The yellow is for any axillary circuit, or brakes. Maybe others have seen this anomaly you refer to Carol, and will chime in.



Even if the did use the center pin for brakes, that would leave open the one normally used for use with backup lights. A quick test with a meter will tell the tale.

[SouthwestOregon201]

Jim's diagram shows the configuration of my new 7-pin connector. I haven't checked to see if my tow vehicle had the yellow(auxillary) wire connected. I can not imagine that a 2012 Tacoma would not be factory connected.

However, Floyd has me thinking that a manual switch with perhaps more than two lights would be very useful. I particularly like the idea of lighting up the sides of the trailer, facing down and out, that would be very useful.

I have a couple of utility trailers with 4 pin connectors, and home made pigtails showing the yellow(left brake), green(right brake), brown(tail light) configuration that Carol uses. One of those trailers has wiring that is pretty lengthy and I have never had a relay involved, so I guess I'm okay in that regards.

I've got so many DC lines coming out of my new PD4045 that needed a place to go. I'm now thinking that my view backing will really be enhanced. I will call that the 'Floyd' lights.

Dave Heffner
Again, thanking the group for ideas.
Roseburg, OR

[EcoHeliGuy]

I have wired my reverse lights to the 7 pin harness through the connection box where the harness branches off. I also added a light switch to the out side of the trailer. My tow vehicle isn't equipped with the 7 pin wired for reverse lights.

If another tow vehicle is equipped, then the lights will be activated as normal. While disconnected or connected to a tow vehicle without proper wiring, a simple flick of the switch by the door illuminates the reverse lights when needed from the trailers battery.



Sent remotely

[Bob Miller]

I agree with Jim, I have never seen the center pin used for anything except Back-up/Aux use. To add to that, there are any number of 7 pin socket testers on the market that are labeled as to which LED represents what. If someone reinvents the configuration they will display incorrectly.

[Bob Miller]

Originally Posted by EcoHeliGuy

I have wired my reverse lights to the 7 pin harness through the connection box where the harness branches off. I also added a light switch to the out side of the trailer. My tow vehicle isn't equipped with the 7 pin wired for reverse lights.

If another tow vehicle is equipped, then the lights will be activated as normal. While disconnected or connected to a tow vehicle without proper wiring, a simple flick of the switch by the door illuminates the reverse lights when needed from the trailers battery.



Sent remotely

Not only that, you might want to be able to turn those lights ON when you aren't connected to the tow rig. Or, you could wire it both ways just by tying in a simple switch between a fused source on the trailers battery and the line to the lights.

[Joe Romas]

The factory installed 7 pin connectors on my past 2000 Jeep Cherokee, 06 Jeep Liberty and 07 Silverado all use the center pin for the backup lights that correspond to how my 1999 Casita 17' is wired.

I think Carol's wiring diagram is used on tractor trailers.
Can any 18 wheelers verify that?

Joe

[Jim Bennett]

Originally Posted by Joe Romas

I think Carol's wiring diagram is used on tractor trailers.
Can any 18 wheelers verify that?

Joe

Well, I have a Class I license to drive the buggers, but have not worked on the wiring of them. I don't think this would be the case though, as all the big trucks I have driven use air brakes. I do wonder about the electric over hydraulic brakes though.

[mary and bob]

To answer Jim; Big trucks / tractor trailers use two pins for tail & marker lights, all the markers are not on one circuit but split. That's so if one fuse or breaker fails some of the lights are still on. Brake lights are another pin. That leaves one pin for left turn, another pin for right turn, one pin for ground. The remaining center pin is an auxiliary circuit, could have been used for interior lights in a dry van trailer, newer trailers may have used it for the ABS circuit. Been retired from working on those big trucks for 4 years now, trying to forget about it. Never saw a trailer with electric over hydraulic, all the ones I worked on were air brakes. In the northeast we were constantly repairing wiring and lights. So disregard this wiring setup for RV's.

[Jim Bennett]

Originally Posted by mary and bob

Been retired from working on those big trucks for 4 years now, trying to forget about it.

Doesn't seem to be working.

Thanks for 'splaining things.

[mary and bob]

Originally Posted by Jim Bennett

Doesn't seem to be working.

Thanks for 'splaining things.

Well it's working a little bit because I had to think some on what we used the center wire for. Then some trailers were wired so the interior lights on the dry van trailers would only work with the parking brakes on. That created more wiring and a air sensor which translates to more problems. But back to the original topic: yesterday a lady came into the campground with a Casita 17. Lot of trees to watch out for so I was just watching her back in (which she got it in place in one try, no pull ups) and noticed her trailer has built in back up lights and they worked. Now we just bought in November a '96 LD 17 Casita and a 2012 Ram pickup to tow it south for the winter. Got both just a week or so before we left home so no time to do anything except grease the wheel bearings, check brakes, install a high mount stop / turn / marker light, and away we went. Never noticed our Casita also has backup lights. Don't know if they work and won't know for another month. Can't get the truck to the trailer because we have a screen room in front of the trailer.

[Carol H]

Originally Posted by Jim Bennett

T I have never seen other than the blue used for brakes. <cut>

Even if the did use the center pin for brakes, that would leave open the one normally used for use with backup lights. A quick test with a meter will tell the tale.

Jim mine does use the blue for the brakes. Except its located on the center pin. If you scroll down on the e-trailer link you will see near the bottom the diagram that is set up as mine is. Its called the "Heavy Duty Truck 7 way Trailer Color Code". Would do the cut and clip as you have done for yours if I had a clue as to how to do that!

[Carol H]

Ok so I figured it out! LOL This is how my truck is wired up - although its not a round pin its a seven blade and its a perfect match to how Scamp also did their 7 pin connection for years (as per their manual) & how my connection is wired up though its a blade type on my trailer - although I understand that in VERY recent years (last 4 or less) Scamp changed it to be more as you have noted the Standard 7 pin to be.

[mary and bob]

So Scamp used two tail / marker light circuits and separate brake light circuit? That's good to know if I ever have to work on one. Any idea which circuit powers what lights? At rallies I seem to be the one that gets asked how to fix things and the one with tools.

[Darral T.]

Here you go M&B. This is the way my 2010 Scamp is wired and as Floyd said, with "Factory" backup lights. I use a rear camera in my Scamp and at night if backing in, the lights REALLY helps the camera!

I made this drawing awhile back because I wanted to test the rear trailer lights. Now I can by "jumpering" between the "Black" or "HOT" and any of the other tail light, brake lights, etc. blades. It works but you have to be VERY careful and not short anything. Hope this drawing helps....

https://www.flickr.com/photos/50351683@N08/9728844401/

Originally Posted by mary and bob

So Scamp used two tail / marker light circuits and separate brake light circuit? That's good to know if I ever have to work on one. Any idea which circuit powers what lights? At rallies I seem to be the one that gets asked how to fix things and the one with tools.

[mary and bob]

Thanks Darral, same as my Casita. So in Carol's photo the brakes must use the center pin? All the other pins are lights and a ground. That's the plug commonly used with an air brake trailer which would have two circuits for tail & marker lights, left and right turn in the outer tail lights and stop in the inner lights.