No brake lights

[jscraig]

Hello all. I'm in need of assistance. I have a shamrock 19, and am traveling to florida. I seem to have lost my brake lights and signals. All of the other exterior lights are functioning. I have already replaced the bulbs just to be sure. This did nothing. Any help would be greatly appreciated.

[emm-dee]

What's your tow vehicle? Some of the newer model trucks have separate fuses for the 7-way connector.

[jscraig]

Originally Posted by emm-dee

What's your tow vehicle? Some of the newer model trucks have separate fuses for the 7-way connector.

2013 silverado 5.3

[TURBS]

Your truck will have trailer fuses up in the engine compartment


2015 Columbus 320RS
2008 2500HD Duramax
2015 nights camped "34"
2016 nights camped "14"

[jscraig]

I sure hope that's the problem. If not I guess I'll keep my wife close on my tail. We are taking two vehicles. Then when I set up, I'll have 6 days to fix it right.

[f5moab]

Two fuses blowing at the same time? I would wonder if there is a separate ground circuit for the brakes/flashers on the trailer (they are the same hot circuit). But here's a wiring schematic for a 2013 Silverado... Hope it helps....

[emm-dee]

Silverado owners manual, Page 10-41, shows Fuse 1 and Fuse 3 control trailer left and right turn/stop lights. May or may not be the problem, but if they are failed I think you should try to find out what caused them to short out in the first place.

[rockfordroo]

When you say all the other exterior lights are working, I'm assuming you mean the yellow and red clearance lights at the top of the TT??

If so, then your problem is NOT the tow vehicle (at least not for the tail light circuit, which also powers the clearance lights). I suspect you've lost the common ground associated with the tail lights and brake lights. On my Roo 19, you accessed these by removing the thin plywood panels that FR installed on each end (left and right side) inside your rear storage compartment.

As I recall, the wiring for the rear top clearance lights drops down and is tied into the tail light wiring. There will be two separate power wires coming from the front of the trailer, one for the tail lights and one for the brake lights. But there is only one ground wire. But this ground wire has to tie into the ground wires for all the clearance lights, tail lights and brake lights in the back of the TT. This ultimately requires a number of splices into the ground wire. I suspect that the ground wires for the tail lights and brake lights may have been tied together, and then to ground, but that connection has been broken.

Hope this helps. Good luck.

[f5moab]

Two fuses blowing at the same time? I would wonder if there is a separate ground circuit for the brakes/flashers on the trailer (they are the same hot circuit). But here's a wiring schematic for a 2013 Silverado... Hope it helps....

[jscraig]

Mr Rockford. Do you recall if this ground is on the driver side or passenger side of the TT?

[rockfordroo]

There is a junction box under the trailer. Look at the frame just behind the battery box on the drivers side.

The ground wire comes from this junction box. There should be 2 of them, because one of them needs to go forward to provide a ground for the front clearance lights. (You'll see a power and a ground wire in your front storage for the front clearance lights).

The rear ground runs back on the drivers side of the frame and comes up into the rear storage compartment on the drivers side. The power wires for the brakes and tail lights should also do the same.

If you have trouble figuring out which wires are ground, remove the cover of the junction box. The largest wire nut on the largest number of wires should be the ground. It will be one of those "largest number of wires."

Here's an overall wiring diagram of the circuit:

http://www.actionoutboards.com/trailerwiringdiagram.pdf

The one problem with this diagram is that it doesn't show the ground wiring; each lights ground wire is assumed to be attached to the metal frame of the trailer. This is basically used on boat trailers, but RV's actually wire the grounds together and run them back to the junction box. It doesn't matter which lights ground hooks into the ground wire in which order, so long as it does. The entire ground wire is "electrically ground." The problem is that they may hook the grounds of the right tail light and brake light together, do the same to the left tail light/brake, then hook those two grounds together, then tie in the clearance light grounds. So if something came apart, depending on how they did it, it could leave the clearance lights attached to ground, but the tail lights/brakes unattached to ground.

[rockfordroo]

Originally Posted by jscraig

Hello all. I'm in need of assistance. I have a shamrock 19, and am traveling to florida. I seem to have lost my brake lights and signals. All of the other exterior lights are functioning. I have already replaced the bulbs just to be sure. This did nothing. Any help would be greatly appreciated.

JS: I just read your OP more closely and it sounds like it's ONLY the brake lights that are bad. If your turn signals are working, then you definitely have a tow vehicle (TV) problem. If your turn signals aren't working, that would point to either the tow vehicle (TV) or the 7-pin connector as the most likely culprits, as previous posters have given you info on.

[f5moab]

If the turn signal and brake lights work on the vehicle but not on the trailer, I would just disconnect the 7-pin and check for power to the brake/turn signal wire at the connector. If there is power with the brakes applied and/or turn signals on, then the problem is from the trailers side of the connector through the trailer.

[RSchleder]

Most issues with 12V lights are a bad ground. However, since some of your lights are working that doesn't sound like it's your problem. Do you use a spray can of Electronic Contact Cleaner ( plastic safe)? I always carry a can and spray both the TV and the trailer plugs and my light problems have disappeared since I started using this a few years ago.

[Cooksonthego]

There's another trick to do a quick check to see if the trouble is before or after the 7-pin. Since I have trailers that also have 4 pin connections, I have a 7-pin to 4-pin adapter which has indicator lights built into it. If I have a problem (and I have ) I plug it in and see if it lights up (running lights, brakes, turn signals). If it doesn't flash like it is supposed to do , then I start checking the fuses. If you pull multiple trailers, it is easy to have a problem with one and not notice it. Best 11.95 I've spent in a while!!!

Bill

[f5moab]

I have one of these, which is very over priced, but purchased used from a neighbor at his garage sale, who sold his trailer.

But most people have a voltmeter (not all, but most), or if in a campground, I bet if you smiled nicely, and walked around, someone would have one you could borrow...maybe.

But your idea is sure a lot less expensive than a dedicated tester.

[Cooksonthego]

That looks like a dedicated tester. Mine is a pass thru; my 4-pin trailer plugs into the unit which has lights. That is WAY more hi-tech.

Bill

[rockfordroo]

Originally Posted by Cooksonthego

That looks like a dedicated tester. Mine is a pass thru; my 4-pin trailer plugs into the unit which has lights. That is WAY more hi-tech.

Bill

Like this one:

https://www.etrailer.com/Wiring/Hopkins/47345.html

[emm-dee]

If just checking for DC voltage thruput this is a cheap way
test light - Walmart.com

[f5moab]

Originally Posted by Cooksonthego

That looks like a dedicated tester. Mine is a pass thru; my 4-pin trailer plugs into the unit which has lights. That is WAY more hi-tech.

Bill

Yours is also LESS expensive too. I was lucky, I got this in a garage sale, I believe Amazon price is around 35 bucks. Only time I ever used it was when installing a new plug on my Hummer after I tore the old one off.