clearance lights T-1850

[barryy]

I hope someone can shed some light on a lighting issue..
I have a 1985 T-1850(goose-neck). I have all 7 marker lights and tail lights working but the 4 marker lights in the front of the coach do not light.
I have determined this is likely a ground issue..My question is..Has anyone had the interior paneling off to see where Sunline routes the light wires running to the front marker lights?
I want to know where the break in the ground is so I can fix it properly.

thank you

[JohnB]

Welcome barryy!

I agree with you, it does sound like a grounding issue. I have not had one of the 85 campers apart, but assuming Sunline used the same wire routing method over the years, see if this fits.

At the front wall, just about behind or at the frame header at the front bottom of the camper underneath (since you have a gooseneck), the hot and ground wire for the front wall would go up the wall from under the camper. The DOT light wires are out in the open under the camper except at the front and rear wall. Assuming they used the same color codes as the RV industry, a green hot wire (running lights) and a white ground wire would go up into the front wall cavity. Then they daisy chain jump from light to light wire nutted at each connection. I have seen the wire nut connection get corroded. The newer campers have the nut siliconed shut to try and help the corrosion, but is does not always seal totally. Not sure what year Sunline started that practice.

Look at that area under the camper up front for white stranded wire. The 7 wire truck cable also has a white ground at that area, as well as the battery and most likely the LP gas pipe making all frame ground connections. Sunline used white stranded wire as the DC ground. It may be that the connection to the frame is all corroded and needs to be cleaned up.

If you want to confirm that the ground is the problem on the front marker lights, maybe try this. Pull one of the light fixtures apart and look for the white wire connection behind it. There should be white and green tie in points. Then take a long jumper wire and connect one end of it to a known good ground. Maybe the battery negative or ideally where the 7 wire cable ties into the white grounds at the camper. Then take that long test wire up to the white wire behind the front marker light. Using a volt meter, with the truck running lights on, check for 12 volts between the green hot wire at the light and the test ground wire. It should show voltage and would confirm that the green is hot and it is getting power. Or tell you you are loosing the hot wire. Also check the white at the fixture for voltage to the test ground. It should be dead, but never know if someone mixed up the wiring polarity.

If the green is getting voltage, it points to the ground. Then touch the ground test wire to the white wire at the light and maybe all 4 of them light up. That would confirm the ground on all 4 are lost and you have to find where that ground came unhooked or not making good contact.

Also check all the light fixtures, meaning take them off the camper and inspect the wire nut connections from the fixture to the camper wiring. Since they jump from fixture to fixture in the wall, the ground or hot splice at the first connection may be corroded at the fixture and preventing all of them from working.

Taking the front wall apart to chase this would be the very last thing you want to do. If it comes to this, lets talk first on how to do that.

Hope this helps

John

[mainah]

Because the wires do not individually go to each marker it has to start somewhere to begin the chain the last one will have only one set of wires the rest will have two. So find the one with one set and count back to the first one. With poor connections a voltmeter can often fool you because it offers almost zero resistance and may trick you into thinking you have voltage, a 12 volt test light would be a better choice because it loads the circuit.

[barryy]

Thank you John
I have traced the DOT light wires from the 7-way to the where they run to the road side rear...where they disappear behind the paneling of course. Logic would say they run to the curb side tail then lower marker lamp then daisy chain as you said up to the upper markers and then along the road side to the front...I say the road side because the lamps all have 2 green and 2 whites...(one in and one out per color) until you get to the lower curb side marker where there are one white and one green. Stands to reason that this is the last lamp in the series. Now my dilemma...All lights(DOT) work except the front 4 which I stated earlier.Suggesting a break in ground somewhere between last rear marker and first front marker.
BUT....a test light hooked between the *white and a ground* lights the test light...when test light is hooked between *green and ground* the marker lights energize.
This seems opposite of the expected outcome. I get this same result no matter which of the 4 forward mounted marker lamps I test.
I would run a jumper wire from one of the forward lamps to chassis ground except that it goes against rationale to attach a green to a ground..though that is what makes the lamps work. A note: Nothing in the coach appears to have been disturbed. I.E.: Paneling, wiring, nothing to suggest this coach has been tampered with in it's 25 years...Actually the reason I purchased because it is nearly perfect inside and out.
I don't know...
Thanks for any insight
Barry

[barryy]

Yes...Thank you mainah...I have been utilizing a test light and I have power at all 11 marker lamps...so in my experience this has to be a ground fault issue

[mainah]

OK you can test the ground with the test light either at the + lamp terminal or connecting the test light to the + on the battery with the clip side of the light. If the ground is good the light will light. If everything looks fine I would have a really good look at the first lamp in the chain as it supplies all the others the point of ground on the camper probably is less likely because the lamp is exposed to the weather.

[barryy]

right...yes the first in the series..or the one we can assume is first...lower rear curb side...lights up as do all the rear lamps...it's between there and the front lamps...the trouble is at some point between rear and front.
i guess i am down to removing panels to expose wires or just let it be.

thanks guys

[mainah]

Here is where the fun comes in logic would say there is a central point of wiring from the 7 pin somewhere up front maybe near the fuse panel. What you can do to make things a bit easier. As long as you have the camper battery installed stuff a bear wire in your your 7 pin connector between pins 3 and 4 this will light your marker and tail lights so you don't have to plug it into the TV.

[JohnB]

Originally Posted by barryy

Thank you John
I have traced the DOT light wires from the 7-way to the where they run to the road side rear...where they disappear behind the paneling of course.

Logic would say they run to the curb side tail then lower marker lamp then daisy chain as you said up to the upper markers and then along the road side to the front...I say the road side because the lamps all have 2 green and 2 whites...(one in and one out per color) until you get to the lower curb side marker where there are one white and one green.

Stands to reason that this is the last lamp in the series. Now my dilemma...All lights(DOT) work except the front 4 which I stated earlier. Suggesting a break in ground somewhere between last rear marker and first front marker.

BUT....a test light hooked between the *white and a ground* lights the test light...when test light is hooked between *green and ground* the marker lights energize.

This seems opposite of the expected outcome. I get this same result no matter which of the 4 forward mounted marker lamps I test.

I would run a jumper wire from one of the forward lamps to chassis ground except that it goes against rationale to attach a green to a ground..though that is what makes the lamps work.

A note: Nothing in the coach appears to have been disturbed. I.E.: Paneling, wiring, nothing to suggest this coach has been tampered with in it's 25 years...Actually the reason I purchased because it is nearly perfect inside and out.

Hi Barry,

First, you get an A+ for your troubleshooting and posting about it! This one is an odd one. We all learn from these posts, and how you work your way out of them. This is good for all!

I do not think you are "yet" at the point to start removing panels or to just leave it. Something is not totally adding up just yet.

Lets confirm a few things. The front area 4 marker lights, 2 on the top front wall, and one on each front left and right side. All amber lights. Yes, those are all parallel daisy chained together. And it seems that green and white wire that feeds the first in the chain is the problem at the moment.

To the green and white feed wire routing on the front wall. I'm not sure "yet" that the green and white come from the back of the camper, up to the front of the camper. We did not yet talk about the junction between the 7 wire truck cable to the camper DOT wires.

Need you to check and confirm what I am going to talk about. What you described on the rear of the camper does fit with how Sunline even wires the newer campers. The DOT wire bundle runs from the 7 wire cable junction all the way to the back wall under the camper where you can see it, then it goes up into the wall to never be seen under all the siding etc.

See here on one of my Sunline project campers I am rebuilding. This the back wall and we tested the DOT lights by jumping the 7 wire plug pins to make darn sure all the lights work before we put the siding on. This is how I feel yours is wired like, as it fits your word description.


Now, how do they get a green and a white marker light feed to the front wall area? Here we need you to confirm a few things. On a 2003 camper, Sunline started the front wall green and white wire feed "at the 7 wire cable junction". Meaning they had 2 green and white wire feeds. This all starts at the 7 wire cable. One green run, goes to the back wall. A 2nd run starts the 7 wire cable junction and goes up into the front wall. But, this was what was done in 2003. Yours was built in 1985. Did they create that front wall feed, at the back wall and run it all the way to the front, or create the front wall feed at the 7 wire cable junction? Good question, I know.

See here for my project camper on the front wall. The green and white come-up from bellow into the front wall, then parallel daisy chain from each amber light until they get all 4 of them.


Please find the end of the 7 wire cable where they spliced into it creating the rear wall green wire feed. Look if there are 2 greens at that cable splice running into the camper, one to the rear and the other somewhere else, like the front wall? Back in 1985, that junction may be just all electrical taped under the camper OR come up inside the camper into a wooden junction box inside the camper with 2 fuses in it (truck charge fuse and battery charge fuse) and the joining of the rest of the DOT wires (the brown, red and yellow if yours has back up lights.) If yours has that junction box up front inside on the floor most times , that is a key piece of info. They bury that box under a cabinet or sofa etc pending the floor plan. Does your have that junction box? The front wall green feed wire could start in that box, go through the floor and then up to the front wall so you cannot see any of this under the camper.

If you can find the start of the 2nd green wire, that creates a place to trouble shoot from.

Now this statement. I have a possible explanation for this.

BUT....a test light hooked between the *white and a ground* lights the test light...when test light is hooked between *green and ground* the marker lights energize.

What you are describing sounds like a wire color polarity mix up. The test light is a helpful tool, but it does not tell polarity and it can act as a jumper wire with a resistor in the middle of it. Try using the voltmeter and confirm which wire, green or white is the positive wire? I can see how a test light will give you the results you found if the wire color polarity is mixed up.

It is not beyond belief, that the camper was built with a wire color mix up. It happens. Incandescent light bulbs do not care about polarity, they will work either way. Just it makes it hard for someone 35 years later to trouble shoot, it... Like maybe, you.

Find the 7 wire cable junction into the DOT wires, the polarity of the front wall green and white, are now more clues to the problem.

If you find that wooden junction box, take some pics of the inside of it so we can see how many green wires are joining to the 7 wire cable. Also look, how does the white 7 wire cable wire tie into the camper DC ground wires. That white wire junction may be part of the mix up/problem too.

Hope this helps and curious on how you make out.

John

[JohnB]

Here is some more help.

The jumper Mainah is talking about. This diagram from Etrailer, shows the pins on the end of the 7 wire plug. Look under "7 wire RV standard" in the middle of the picture. Jump between the 12 volt power and the tail and running lights pin. They are right next to each other.



That wooden 7 wire truck cable junction box you are hunting for, Note the 2 greens tied into the 7 wire cable.

Here are pics from a 1998 Sunline,



Here are pics of a much older one. I believe an 80's vintage camper. Note the black wire loom, there is a green and white going to it. On this camper, that is the front wall DOT light feed.


You can see the green and white in the wire loom






Hope this helps

John

[mainah]

Remove all of the bulbs from the front markers and try your test again.