Exterior light question

TerryV6

I’ve never noticed ‘‘this before.  We haven’t camped this year, but have the camper in the driveway, where my wife loves to go and read.  I had the camper plugged to shore power.  This evening I unplugged.  We have our battery disconnect inside, to the left of the bathroom.  That switch I put in 2-3 years ago, following a mod I found here. I turned that switch off too.  We noticed that the back red lights outside are still lit.  Any ideas?  Did I miss something?

TerryV6

Those red lights.  Aren’t they running lights that are lit when connected to the TV.?  Could it be a dirty 7 pin connector or something?

N7SHG_Ham

Those lights should have zero connection to the trailer battery/shore supply. So, somehow there is power reaching the outside lights, I have seen bad grounds cause this, it isn't magic, but it may be hard to track down the electrical path. I would start at the light itself and make sure the wiring is clean and tight.

ScottG

Were all four of the marker lights on, or just that one? Is it as bright as when you are connected to the tow vehicle? Did it go out eventually?

ontheroad

Previously on our T@g we had some water get into the  7 pin connector..it lit up a tail light..only one side though...got it cleaned out and it was nice and dark...now we cover the connector

TerryV6

Scott, we just noticed it last night.  It is the two lights in back.   We only connected to TV in March to bring her home to prepare for a season that hasn’t happened. This isn’t a political statement, but my wife was in healthcare for 40 years and knows and has seen a lot, so we don’t dismiss the present situation.  

 Anyway, I’m going out after coffee here and see what’s what with my connector, as per previous suggestions here.  We’ve had tons of rain.

BrianZ

I'm wondering how you leave your 7-way plug when not in use.  We've never used a cover for ours, but I do try to make a point of leaving a short length with plug hanging straight down for drainage.  We've never used a cover & never had an issue, though we're probably overdue for cleaning the contacts & applying some dielectric grease.

TerryV6

Well the 7 pin connector was not the first place I would have looked, but...
My wife had purchased a rubber cover for it and we always left the cable at a  downward angle.  I took the cover off and was surprised to find it was full of water.  TaDa!!  Problem solved.  I’ll have to clean the connections of course, but now its lights out, somebody home.  Thanks all..   PluncK!!!  That’s the sound of the cover hitting the trash bin.  2 points!

Bayliss

@TerryV6, I think you can keep the cover (or purchase a new/better one.)  Just keep the plug pointed up, which is what I do when it is covered (down when not covered.)

falcon1970

I agree with Bayliss.  Keep the cover but point it up.  This is my solution to containing all the attachments;

  

Tampakayaker

I have ours tucked into the propane/battery tub.

Bayliss

Does anyone have a theory as to why only the rear end side-marker/running lights (if I am correct about that) on @TerryV6's trailer illuminated under the circumstances he described?

Although I initially suspected water on the 7-pin plug, the description of only those two lights being illuminated threw me off.  That circuit should control all four side-marker/running lights (i.e., front and rear sides), the license plate light, and both of the tail lights.  Although there is only one wire for those lights from the 7-pin plug, if you trace the connections from the junction box at the front of the trailer, there are two wires leading to those lights, presumably one wire to each side of the trailer.  See the junction box diagram below for a 2019 T@B 320 S - - I am referring to terminal #3 with the green wires.)

So, why wouldn't ALL the lights on that circuit illuminate under the described conditions?  Just curious.

SeaLaVie

I have this little attachment and really like it. https://www.amazon.com/dp/B01MFFC0IU

BrianZ

@Bayliss, maybe those lights had the lowest power requirement?

Bayliss

Possible, I suppose, @BrianZ.  I am not familiar with something like that occurring.  It is really hard to say without knowing exactly how the wires are routed.  You would think that the first light on the circuit would pull the power if it was a low power situation.  I believe that the two green wires from the junction box send power separately to lights on each side and rear of the trailer.  Presumably, the first connections would be at the front side markers, but ya never know.  It is definitely a head-scratcher.  I tried searching online for a possible answer, but no luck so far.

ChanW

Good question!

I think with LEDs, all conventional wisdom might go by the wayside...

Maybe there's a minimum voltage requirement for some of them before they 'fire'?

Just a guess...

Bayliss said:

Possible, I suppose, @BrianZ.  I am not familiar with something like that occurring.  It is really hard to say without knowing exactly how the wires are routed.  You would think that the first light on the circuit would pull the power if it was a low power situation.  I believe that the two green wires from the junction box send power separately to lights on each side and rear of the trailer.  Presumably, the first connections would be at the front side markers, but ya never know.  It is definitely a head-scratcher.  I tried searching online for a possible answer, but no luck so far.

Michigan_Mike

I’ve seen this phenomenon happen for many years now.  The issue with LED lights are that they require minimal voltage and they are sensitive and will power up.  And as noted above, grounds will create issues on occasion with LED lights too.  If voltage somehow is back-fed or leaks into a ground it will create a similar problem.  This is why the battery gets drained too via LED circuits as although they require minimal voltage, their is a constant drain on the trailer battery through LED circuits, DVD/TV, other devices, etc.  

I always just flop the trailer power cord downward to eliminate this issue and and condensation created.  I noticed the condition above about 10 years ago when I swapped out incandescent trailer lights with LED lights and attributed it to a grounding issue on my 4-wide Little Guy.  

BrianZ

@Michigan_Mike, a ground issue sounds more plausible in @TerryV6 's case now that I reread his original description.  I was thinking that the green wire being next to the 12V inside the plug would make it easy to get a short via water inside the plug from the power lead going back to the taillights.  However, this would only be true if the battery switch was turned on to supply power to the cord via the distribution box panel; but @TerryV6 said the battery switch had been turned off when the light was on.  Could there be an issue with the battery switch wiring perhaps?  Some further wiring troubleshooting may be needed.  Maybe take another look at the battery switch wiring?  I'm wondering how that was done.

PS:
I just tested our plug by inserting a U-shaped piece of 14 AWG wire between the 12V (11 o'clock) and Taillights (1 o'clock) contacts inside the plug, with battery switch on & trailer unplugged from ac power.  All six running lights lit up (small front & rear side lights, plus the two large round taillights at rear).  With battery switch off, none were lit.

TerryV6

Well, I’ve never had this happen before, but being a good husband, I always willing to accept blame and perhaps I’ll check my shut off switch. We haven’t been camping and I’ve been distracted by golf and some new toys..

I’ll do some digging to find my info and compare to what I did..

BrianZ

@TerryV6, I'd be curious to see, if you did the test I described under my "PS" above, do you get the same results?

Bayliss

@TerryV6, are you confident that the seven-way plug was not connected to the tow vehicle when the trailer battery switch was turned "off" (i.e., not supplying power to the trailer)?  I don't think you specifically said, but I guess I assumed it was not connected to the tow vehicle.

Since you found that the seven-way plug had water infiltration, I can see it completing the circuit between the 12V and the running/tail light pins even if that plug were disconnected from the tow vehicle, BUT only if the trailer battery switch was on, or somehow defective, which would allow power through to the running/tail lights.

IF the seven-way plug was in fact disconnected from your tow vehicle, and your battery was also disconnected/isolated via the battery switch, then I would agree with @BrianZ that there is a good chance there is something defective with the switch that was allowing power to get to the junction box.  (On the other hand, it sounds like getting rid of the water issue solved the problem, which tends to indicate that the battery switch was not the issue, assuming nothing changed as far as the battery switch and/or battery connection.)

Unfortunately, it is pretty much impossible to re-create the specific circumstances, but if your switch is good AND the seven-way plug was not connected to the tow vehicle, then there must be some "voodoo" magic going on.  Very strange situation, but I sure am looking forward to learning what happened, if that can be determined.

TerryV6

Sorry sorry for the delay. I’m including the one I saw here, and two of mine.

This was what I followed.

Bayliss

Hmmmm.................how exactly is that switch wired?  The two lower photos are blurry, so I can't tell what they are actually connected to.  I have never seen it wired like it is in the first photo.  Specifically, the red wire comes out, goes through the switch, then returns back inside the converter housing.

Doesn't mean it isn't wired properly, but I'm just not sure where the red wires are connected inside the converter.  It appears that the same wire is looping back in to where it starts, with a switch in between.  Is it in fact killing the battery power when you turn it to "off."

ScottG

In this case, the cutoff switch works by disconnecting the converter from the junction box (and therefore the battery) under the front of the trailer.

This configuration means the battery is always connected  to the pigtail (via the junction box) regardless of the position of the cutoff switch. Therefore, water in the plug could indeed route battery power to the running lights by creating a short between the battery and trailer running light circuits.

@TerryV6, I suspect your initial diagnosis was correct. However, why all the running lights were not affected equally is a mystery that remains a bit out of my pay grade!  ;-)

BrianZ

Thanks, @TerryV6.  That pretty much clears things up, and is as I suspected.  So, your switch will still isolate your battery from usage as long as the 7-way plug is both disconnected & protected from shorts by water.  Your switch does have the advantage of protecting both trailer & car batteries [when 7-way is plugged into TV] from being drained by the trailer, though won't protect either from drainage by TV accessories if left on. 

Our switch in the tub will always protect the trailer battery when turned off, but it won't protect our TV battery from drainage by trailer if 7-way remains plugged in; because our 7-way socket is wired directly to the TV battery via a circuit breaker near the battery under the hood, so the outlet is always hot.  Good thing it has a spring-loaded cover though.  We would need to unplug from TV if stopped for an extended period of time, to protect TV battery from trailer usage, regardless of switch position.

As far as the trailer taillights shorting on, I would guess that water inside the plug has limited conductivity (unless there's enough dissolved salt), so the voltage may be low, which would further limit the current through the LED lights (which already contain a current-limiting resistor to prevent burning it up).  If voltage/current is low enough, the LED will stop conducting & change his name to "NED" 😉.  If other lights are using more LEDs with higher internal resistance, they may not turn on at reduced voltage, or the wiring may be longer & have higher resistance.  Circuits are dynamic things that can easily get out of balance & malfunction under less than ideal circumstances.

TerryV6

Sorry for the blurry pics, I'm not used to taking them bending down and facing the camera that way.  I took the back off and tried again.  Thank God for cordless drills.  I remember now that the switch  is just interrupting power from the red wire.  Is there a better wiring setup?  I saw how ScottG did it.

Bayliss

@TerryV6, attached is a wiring diagram that @klenger (no longer a T@B owner) made.  It depicts how nuCamp wires the trailer at the factory (although this drawing is for a 2019 320 S.)

As @ScottG points out, your switch currently cuts the power from the converter to the junction box at the front of the trailer, but it does not prevent the trailer battery from sending power to the junction box.  Therefore, when water penetrated your seven-way plug, that created an electrical connection between the 12V and side-marker tail light pins on your seven-way plug.  Since there is nothing (like a cut-off switch) preventing power from the trailer battery reaching the seven-way plug (via the junction box connection), the battery was the power source (because your switch is not wired to isolate the battery.)  But, as we all agree, that doesn't completely solve the mystery you started with.  (Thank you for providing the additional photos.  That was helpful.)