Wiring Conundrum!

[V'sGlassSleeper]

Background: I had replaced all lightbulbs inside and the porch light with LED bulbs and all were working great. I also replaced the AC and the bathroom fan with two MaxxAir Fans and both of those were working great.

Then, since many of the exterior lights no longer worked and all proved too brittle to keep, I bought all new LED tail lights and marker /clearance lights. Where there were 2 wires of the same color (i.e. two black and two white) that had previously been intertwined and fed into one exterior light, I soldered the two wires of the same color together into one wire to make it easier to fit into the back of the new lights.

I then connected each of the new exterior LED lights to the trailer lights but just with electrical tape to start, as I knew I might need to test the wiring, because none of the new lights came with any wiring color code. From some of the reviewers' experiences, I knew that the polarity might be reversed or the wiring might be wrong the way I hooked them up, since the wire colors for the lights did not necessarily match the wire colors for the trailer. The reviews for each type and manufacturer of light (tail light, clearance marker, etc.) provided different and sometimes contradictory information on what color wire served what function (some reviews of some lights had the white as the ground, others had the black as the ground, some said blue was ground, some said blue was running light, etc). So, now I have them all connected and none of them are working.

What is even more odd is that with all the lights connected, now both of my interior fans and two of the ceiling lights are not working, which makes me wonder if they are on the same circuit as some of the exterior lights and now aren't working because the circuit flow has been "interrupted" by incorrect wiring?? I guess I will have to disconnect them all and try one by one...

Can anyone confirm if an incorrectly wired exterior light could cause all the exterior lights to not work and cause the interior fans and two of the interior lights to not work? Any suggestions for troubleshooting?

I took pictures of how the old tail lights and marker lights were wired but the issue is that the new tail light and clearance marker wires do not match the trailer wire colors, so it is going to be a bit of a trial and error game, I suppose, since again the manufacturers of the new lights provided no color key for their wires, so I was relying on some reviewers whose posts may not have been for the exact same model light as I bought. Any more suggestions from those who are more experienced in RV electrical wiring are much appreciated!

Thank you

[40bpm]

Nice trailer!

Unfortunately, I have no answers for your wiring issue, but maybe try going back to the working baseline if possible. If you remove/disconnect all of the new lights see if any of the other fixtures start working.

If you can get the original baseline working, then try installing a single light and get it working. I'm sure you can guess where this is going .

Let us know how things go. I'm probably not the only one that would like to see the new LED clearance lights. Bigfoot owners want to know. Best of luck.

[DayTripper]

Have you Checked your breakers lately ?

[Borrego Dave]

Being the new fans and interior lights were working before the outside lights were added it kind of sounds like you've shorted something out. But one thing stood out, you said the outside lights didn't work. You may have a broken wire/s that supply those lights. As was suggested, check your fuses/breakers first. Not sure if I quite understand what you soldered together but you may want to go back to your starting point with the outside lights and disconnect them to see if that corrects the inside. LEDs can be tricky, I always test and mark the wires before final connections. Most likely it's minor problem and like we used to say at the shop, "ain't nothing but a thing" .

[Joe Romas]

Possibly the short Dave mentioned has something to do with what you said.

Where there were 2 wires of the same color (i.e. two black and two white) that had previously been intertwined and fed into one exterior light, I soldered the two wires of the same color together into one wire to make it easier to fit into the back of the new lights.

[Jeanne D. in ca]

You can check the polarity on your 12v led lights with a 9 volt battery. Saves a ton of time and guesswork.

[Civilguy]

Val,

An open circuit is a gap where there is no path for current to flow.

A short is a direct path from pole to pole with no load (such as a light or motor) in-between.

You may have both.

If there is a short, there should be a burnt fuse. Otherwise your battery would be running high current through the short. This results in what we describe as "letting the smoke out". Once the smoke gets out, something has been damaged. The old saying is that once the smoke gets out, there's no way to put it back in.

There may be a tripped breaker.

The only real answer is to trace and test and establish what connects to what. Normally this is done before soldering. It's generally easiest to start at the source (power panel) and work outwards, but some circumstances may occasionally favor working the other direction.

I like the 9-volt suggestion. You can also establish what the polarity of the light fixtures is by making up a couple of jumper wires fitted with alligator clips. Connect the fixtures to the battery or other known voltage source with the jumpers. Marking the fixtures with a Sharpie permanent marker to note which wire is positive would be helpful.

I find jumpers indispensable when wiring and testing as they serve to extend the reach of the meter and facilitate testing connections. A meter is of course pretty much indispensable to undertaking any wiring work.

I tend to make connections by tinning stranded wires with solder and using properly-sized wire nuts to complete the connections. I have had very poor experiences with clam-shell and stab connectors.

Be patient and methodical. Draw sketches. Take notes. Fortune favors the prepared.

[squish]

The first thing to do would be look for a wiring diagram for your trailer, but they seem to be sparse on the ground.

There are some decent RV 12v system 101 type videos and blog posts out there
Understanding how these systems are created makes it much easier to fix them.

I would pull the new exterior wiring off yes the work you just did, in addition I would check the fuses or breakers for the interior lights, then start chasing down wire runs. What powers what.
Does your trailer have a house battery? Does it have a charge converter? Power distribution panel for both 12v D.C. And 120v AC?
Are the trailer lights hooked up to the tow rig?
Do the exterior trailer lights only work with a tow rig hooked up?

It's not hard work and it's pretty easy to understand, there's little risk of hurting yourself but you could create a fire hazard if you don't have fused power going to some devices.

Get some basic tools, I like a multi meter but a 12v D.C. Test lamp will work, also a continuity tester and a small 9 or 12v battery to test the polarity of your lamps, on cheap China made LEDs you can't trust their wire colors. Even batch to batch of the same products. Always test polarity with LEDs

The next step is to verify your wires work before you start wiring up lights, this is best done with two people, one needs to do the car controls, brake, headlights, tail lights, blinkers. While the other is making sure the power is getting to the light location. This is a tedious process. Most running lights will run off of the tail lights for power so I would start looking there, the lights may also use common grounds where bundles of wires come together.

[Borrego Dave]

Originally Posted by Byron Kinnaman

SUGGESTION -- Take to an RV shop where somebody understands how trailers are wired. Asking questions here is foolish.

Not foolish at all Byron and not rocket science, just basic trouble shooting. I would venture to say there is more "hands on" experience from members, here that are familiar because of the mods made on their eggs, than at most commercial RV shops. I think he's received the correct answers and can fix it. Then put that info in the 'ol mental toolbox for next time. YMMV

[V'sGlassSleeper]

Thank you for the responses! I ask here because I like learning things and trying to fix them myself if I can. The RV shops want to charge $100-150 per hour, Byron, and if I had that kind of money to spend, I probably would have bought a brand-new Escape 19 instead of a 30 year-old Bigfoot that needed TLC.

I have a voltmeter and have to swing by my auto mechanic's shop to get a K&N air filter installed on my truck, so he's going to show me how to use it to do some of the wiring diagnoses that several of you have recommended and he said to bring in my fuses so he can show me how to test them (I had checked them visually and they all look brand new. I had also flipped and looked at the breakers and they look fine). He thinks it may be a short. I didn't know that i could check the LE polarity with a 9 V battery, so thank you very much Jeanne, for that tip!

I had no choice but to try to extend some of the trailer's wires because they were so short that I could not have attached them to the new lights without extending them. I am not sure how soldering (tinning) 2 wires of the same color together - where the lights were daisy-chained - would have shorted anything unless the wire colors were not correct (i.e., someone prior to me had used a white wire when it should have been a black wire), but checking the voltage should be helpful... will be a major pain in the butt if I have to undo all the soldering, but if I do, I will probably end up running brand new wire to replace some of the old wire in some spots because the old wiring is just too short to hook up to new exterior lights).

I had figured the LEDs might be a little tricky (based on reviews that mentioned that the wire colors on the made-in-China LEDs did not match any wiring codes in the US), so I had only attached those with electrical tape and easily took them all off. There definitely seems to be something interrupting the circuit, as the two brand-new fans and two interior lights that were working before are not working now (whereas two other interior lights and the stove hood fan are working fine)...

Thank you everyone who provided helpful tips rather than telling me to just have someone else do it. I have been on this forum a long time and know that there are some very skilled members who don't mind sharing their knowledge and experience. I am less experienced with travel trailers than with home improvements, but I too have responded and posted when I have had helpful information to share and to me, that is part of what makes this such an engaging and vibrant community - members helping members! If at all possible, I want to find the problem and fix it myself because I like gaining knowledge and building confidence... Unless it's really something requiring more expertise, I have found that a DIY project usually just takes a bit more patience when it's a first-time thing. I have more time than money right now, and I have plenty of patience.

I getting ready for a road trip (will have to share space in my partner's little teardrop for this trip, since my Bigfoot won't be ready), so it may be a month or so before I post my findings and/or the results once I have investigated further, but I will do so - regardless of whether I find and fix or have to bring someone in to help me. Thank you!

[Civilguy]

Originally Posted by V'sGlassSleeper

I am not sure how soldering (tinning) 2 wires of the same color together - where the lights were daisy-chained - would have shorted anything

Val,

Just to be clear, when I spoke of tinning, I meant tinning each stranded wire separately before joining them together with wire nuts. The wires are not soldered together under the method I had in mind.

I don't know that splices are often made up this way, but I've found the approach reliable when the soldered wires are cleaned well, the wire nut is properly sized, etc.

Good luck on your project.

[Franswa]

the outside (driving/brake/marker) lights on the trailer and the coach (interior) lights and fixtures are entirely seperate systems and the two are not connected anywhere....

check under your left dinette seat...you will find your trailer lights entering the trailer and they do not go to the coach fuse panel at all....trailer lights are fused in the tow vehicle's fuse panel....

hard to say at this point where you went wrong/crossed the two systems together....but I'd bet you got a blown fuse(s) in the trailer AND in the TV...

I include two pictures that won't be any help (my system is completely changed over from original)....EXCEPT....you will see where and how the trailer light and brake wires come into the trailer....the trailer is a 97BF, CB model

good luck

[Franswa]

even though yours is an 88 and mine is a 97 I doubt the basic wire layout would be different.....in your trailer, as in mine before the re-work, you have a tight bundle of wires coming through the floor and screwed down to the floor dissapearing along the front bulkhead.....(impossible to follow/trace)....

again in the picture below....the wires have been unbundled/seperated....

the larger black and white wires go from the tounge mounted battery to your coach's fuse panel and power all your interior lights, pumps, fan etc....when you plug into shore power your converter/.charger charges your battery through these same black and white wires


hope this was of SOME help....

[Civilguy]

Originally Posted by Franswa

the outside (driving/brake/marker) lights on the trailer and the coach (interior) lights and fixtures are entirely seperate systems and the two are not connected anywhere....

That's an excellent point!

[ZachO]

I just want to know how well a Nissan Frontier pulls a 19' Bigfoot...

Seeing as it's basically the exact trailer I have, but with a full-size fridge and a little extra space (meaning I'd love to have it!). I would think it's seriously pushing your tow limits unless Nissan really overbuilt that truck. I'm pulling a 17'-er with a very similar truck. With how my truck handles it, I figure anything bigger would be too much.

Anyway!

Good luck with your wiring issue.

[Franswa]

just to try to shine a little more light for the OP.....

the very large black wire/cable, with several wires inside it, is the seven pin trailer connector that plugs into the TV....the large black and white wires INSIDE that cable are the pos. and neg. coming from the TV....

out of the factory the neg. (white) wire from inside that cable would have been joined with the two other whites of the same size (one for battery neg. and one from the coach's fuse panel neg.) with some sort of plastic snap connector....a little further along the floor the white going to the fuse panel would have yet another connector joining another smaller white to it....that wire is the negative for all your trailer running/brake/marker lights

the black, pos. wire would have the same connector joining it with the pos. from battery and a pos. going to coach's fuse panel

I know how you fell because when I first got my trailer all of these splices/connections were ALL bundled together in a big tangled mess and screwed/secured to the floor....it's only when I took it all apart that I understood how the thing was wired...in the end it is all logical but the way it was laid out/installed gave no clue as to what went where or why

and I just went out and checked on mine....turns out the green wire goes to the marker lights on the side of trailer....with a white neg. returning....

Could it be that somebody mistook this green wire for a ground somewhere in the coach and connected a neg. to it?????? Easy to see how something like that could happen as in a lot of other applications green routinely means "GROUND"....or neg.

good luck....

[Joe Romas]

Franswa

There are TWO color standards for 7 pin trailer plugs and wiring.

RV STANDARD and SAE STANDARD. See here.

Wiring Guides

The wires are in the same orintation around the plug, just the colors are different.

Your trailer follows the RV STANDARD color coding as it should. Most but not all travel trailers use the RV standard but if the cable has been changed who knows.

Most people have no idea and try to relate the color coding of the 4 pin flat with the 7 pin RV standard. It's confusing and even e-trailer has it wrong in at least one place.

Why should a RV trailer NOT follow the RV standard.

Joe

[V'sGlassSleeper]

First off, Franswa (Francois), thank you for your incredibly helpful photos and diagrams. I have saved them because I imagine that I will one day want to upgrade some of the components and your diagrams and explanations are golden!

The issue turned out not be anything I did, but just coincidentally that the 7-pin plug had gone bad and was creating a short and blowing a fuse. My electrician (who normally doesn't work on DC systems) graciously stopped by and showed me how to do a continuity test and he checked all my soldering and wiring and it was fine, but the 7-pin is likely the original 30-year old one and seems to be the culprit, so I am buying a new one and replacing not just the plug but the cord, as the rubber sheathing is looking a bit rotted in some spots. Franswa's beautiful photos will help me organize the underseat electrical connection area better.

As far as tow capacity with a 19', my 2007 Nissan Frontier NISMO is a V6 with a 6,000 lb. tow capacity and my 19' is under 4,300 lbs. all loaded. I felt that a 1,700 lb. margin was good for safety and I have to say my Nissan tows the 19' Deluxe Bigfoot like a dream. No issues at all. I would definitely not attempt to tow the 5th wheel 19', as it is a little heavier than the tow-behind and I have the 5 foot short bed truck anyway. I think the beefier NISMO (off-road 4 x 4) suspension and the tow package adds a lot of stability for towing... at least that's my experience.

I will post photos once I have the plug and all the exterior lights replaced. She's really starting to look pretty good given that her prior owners neglected her and I got distracted for 6 years (after buying a fixer-upper house), so am just getting back to the renovation in earnest this year.