Electrical & 12V system

[lucymcdog]

Originally Posted by TG Twinkie

That is good news!
I don't think the right blue wire is for the brakes. Do you know if the trailer had a breakaway switch for the brakes? It might have been for that though. Don't know if there is/was a breakaway switch.
How may 12 volt lights are in the trailer? Just the one in the ceiling. It is possible that a battery sat near where these wires came out of the wall and that all of the hardware associated with a battery; like a fuse panel and or converter could have been removed by PO. But I am thinking that the other blue wire must have gone to a place where there was DC power. Don't know why these wires came out of the wall unless this is where the battery was. We know now that the left blue wire is for the light. The right blue wire should be the 12volt power for the light. The light having it's own switch, it would make sense.
I can't remember if you said there was a place for or even an old converter no converter or DC fuse box in the trailer. Do you know if there ever was a battery in the trailer? Maybe it just used the TV battery. I always thought maybe a battery was there given the size and placement of the blue wires. And the fact that the little glass fuse box was screwed into the wall just above the two blue wires. Nothing was going into the box but there were yellow wires coming out. But there was no venting to the outside for a battery so unless they didn't vent them 50 years ago, I don't know if there was a battery there or not.

Try using the same troubleshooting method you did for the light. Jumper the right blue lead to the screw in the skin. Then with your meter on 2K see if you get a "0" reading on any of the wires in the umbilical cord. Touch the black lead to the skin; make sure it's on a shiny spot then touch each of the wires for the umbilical cord. Of course it should not be connected to the TV. Didn't have much luck with this. Here's the readings for the umbilical cord with the "A" clip on the right blue wire and a screw in the wall, the red probe in the colored wire and the black on shiny skin:

Brown - .002
Red, Green, Blue, white - 1
Yellow - .001

Look for a lonely blue wire on the tongue that might have gone to a breakaway switch. Could not find a lonely blue wire on the tongue.



I'll be gone on Saturday and Sunday, but will check back as soon as I can.

See my response to Minno for other tests I did.

[lucymcdog]

Originally Posted by Minno

Umbilical Wiring:


All of the wiring runs inside the walls, except for the battery and brake wires. Those run under the floor, inside the belly pan. I took the piece off that goes around the bottom of the trailer (only just above the umbilical cord) and there were no wires that I could see. The umbilical cord comes out from the belly pan, not the wall of the trailer. It looks like it is actually coming out from under the wall of the trailer. I have not yet cut a hole in the interior wall to see if I can see any wires but will do so if you think I need to.

In looking at the stump of your umbilical cord, it looks likes you have the right colored wires going into the trailer (red, brown, white, blue, green, & yellow). I would start by verifying that the white wire is indeed ground/neutral. Use your multi-meter to see if the white wire is connected to the frame & shell by checking for a zero reading on the 2K ohm setting. Could not get a "0" on the white wire - only "1". If it’s ground, then connect the negative lead on the your charger to the white wire, shell, or the frame, and then connect the positive lead on the charger to each colored wire, one at a time, and see if the corresponding light(s) come on. For example, the yellow wire should light up the back-up lights. The green wire should light up the running lights. Skip the blue wire for now. Even though I didn't get a "0" on the white wire I went ahead and connected the charger to each of the lights with the negative lead hooked to the frame. Nothing worked. So, I opened up all the lights and it is understandable why nothing worked. They are a mess and the bulbs are probably burned out (the least of my problems!) as well. I will be ordering new running lights and hope to be able to use the existing tail lights. We'll see...

If those all check out ok, then the umbilical wiring inside your trailer is basically good.

Now for the blue wire. First, make sure it’s NOT connected to the frame with the multi-meter (same test you used for the white wire stub). Next, see if it’s the same wire as one of the two blue wires inside the trailer. You’ll probably need an extension wire to lengthen the lead on the multi-meter. Clip one lead to the right or left wire inside the trailer, and then check for a 0 reading on the 2k ohm setting by connecting the other lead to the outside blue wire stub. I’m betting that one of those wires indise the trailer is connected to this blue wire. The question is: which one? The one that also connects to the light, or the one that isn’t? I hooked an "extender" wire to the right blue wire inside then took the other end around to the umbilical cord. The multi-meter stayed on "1" for everything EXCEPT the tiny little stub of yellow wire that was there. With the right blue interior wire and the yellow umbilical cord wire connected by the multi-meter, I actually got a "0" reading. Go figger...

The outcome of these tests will determine what we need to do next. Advertise the trailer for sale as is????

Chris

After taking loose all the outside lights on the trailer this is what I found:

Running lights on curbside - 1 green wire from trailer tied to 1 green light wire
Taillight - curbside - 1 black wire from trailer which was loose, 1 brown wire tied to 1 black light wire plus 2 green wires to 1 green light wire
Taillight - streetside - 1 red wire from trailer tied to black light wire and 2 green wires from trailer to 1 green light wire
Running lights on streetside - 2 green from trailer tied to 1 green light wire
License plate light - 2 green from trailer tied to 1 black wire which was then tied to 1 yellow wire which went to the light.

Is it hopeless?

[lucymcdog]

Originally Posted by TG Twinkie

About the switch for the pump near the sink. What color are the wires if any?
Let me know.

The wires that are under the sink and hook into the on/off switch and the little red light (that were once connected to the old water pump?) are yellow, black and ground. See picture.

[TG Twinkie]

You don't have to wait to get your new exterior lights to find out if the wiring is OK. Since you could not get a continuity reading from the white wire to the frame of the trailer; just clean a place on the frame where there is shiny metal showing then connect the negative (black) lead of the charger to that spot. Next connect the red lead of the charger to the green wire of the umbilical cord. Then with your meter set on DC volts; touch the black probe of the meter to a shiny spot on the skin (it must be a good connection). In looking at the pics of the light fixtures, none of them look like they had a good ground, so when you install the new fixtures make sure you use new sheet metal screws and that they tighten down firmly. Since the fixtures all look bad you could just remove them and check for voltage at the wire coming out of the trailer. Strip back about 1/4" of the insulation. Make sure the bare part of the wire does not touch the skin. Touch the red probe of the meter to the wire. If you read between 12 and 14 volts, the wire is good. Have your meter set on the DC volts setting. On the tail light fixture is you don't want to remove them, just take the bulbs out and check for voltage at the contact point(s) in the bottom of the socket. I think you get the idea, using the same procedure check the red and brown wires; they should be the left and right turn signal respectively. You may not have backup lights. Lets see how much success you have with this.

[TG Twinkie]

This is getting a little nit picky but I have to say it. Minno has refered to the DC ground as "ground/neutral". This terminology is not correct. In DC circuits "ground" and "common" are often used to describe one side of the circuit. The term "neutral" is used only on AC circuits. They "ground" and "neutral" are two very different animals.

[lucymcdog]

Originally Posted by TG Twinkie

You don't have to wait to get your new exterior lights to find out if the wiring is OK. Since you could not get a continuity reading from the white wire to the frame of the trailer; just clean a place on the frame where there is shiny metal showing then connect the negative (black) lead of the charger to that spot. Next connect the red lead of the charger to the green wire of the umbilical cord. Then with your meter set on DC volts; touch the black probe of the meter to a shiny spot on the skin (it must be a good connection). In looking at the pics of the light fixtures, none of them look like they had a good ground, so when you install the new fixtures make sure you use new sheet metal screws and that they tighten down firmly. Since the fixtures all look bad you could just remove them and check for voltage at the wire coming out of the trailer. Strip back about 1/4" of the insulation. Make sure the bare part of the wire does not touch the skin. Touch the red probe of the meter to the wire. If you read between 12 and 14 volts, the wire is good. Have your meter set on the DC volts setting. On the tail light fixture is you don't want to remove them, just take the bulbs out and check for voltage at the contact point(s) in the bottom of the socket. I think you get the idea, using the same procedure check the red and brown wires; they should be the left and right turn signal respectively. You may not have backup lights. Lets see how much success you have with this.

With the meter set on DC volts (20) I got readings from 19-24 on all the running lights and the green lights in the taillights. Then I connected the charger to the brown wire in the umbilical cord and meter read 24-25 on the brown wire in the taillight. Did the same with the red wire in the other taillight and got similar readings. I don't have backup lights.

So, does that mean that my wiring will work? Problem is that the cord coming out of the trailer is such a mess. There are just barely any wires sticking out and the yellow wire is about 1/4" exposed. I tried pulling on the cord and it wouldn't budge. Even if I am able to connect the cord to it the connections will all be on the outside of the trailer. Seems that might not be a good thing. What do you suggest?

I will be picking up an Optima battery this week and it looks like it, and the box, will fit on the tongue. So that is where it will go. I have also ordered a breakaway switch that should be in next week sometime with my new running lights. I am unable to find new "bases" for my taillights so I will either try to clean up the ones I have or keep looking.

At least today has been better than yesterday.

Thanks for your help.

So, for my own edification, in a DC circuit, the "black" is the ground or common and the red is the "hot"? In AC black is hot, white is neutral and green is ground, right?

[ck21084]

Originally Posted by lucymcdog

With the meter set on DC volts (20) I got readings from 19-24 on all the running lights and the green lights in the taillights. Then I connected the charger to the brown wire in the umbilical cord and meter read 24-25 on the brown wire in the taillight. Did the same with the red wire in the other taillight and got similar readings. I don't have backup lights.

So, does that mean that my wiring will work? Problem is that the cord coming out of the trailer is such a mess. There are just barely any wires sticking out and the yellow wire is about 1/4" exposed. I tried pulling on the cord and it wouldn't budge. Even if I am able to connect the cord to it the connections will all be on the outside of the trailer. Seems that might not be a good thing. What do you suggest?

I will be picking up an Optima battery this week and it looks like it, and the box, will fit on the tongue. So that is where it will go. I have also ordered a breakaway switch that should be in next week sometime with my new running lights. I am unable to find new "bases" for my taillights so I will either try to clean up the ones I have or keep looking.

At least today has been better than yesterday.

Thanks for your help.

So, for my own edification, in a DC circuit, the "black" is the ground or common and the red is the "hot"? In AC black is hot, white is neutral and green is ground, right?

I have not been following your thread however anything above 15 volts can damage things very quickly. If you are installing a 24 volt system your readings seem correct however I don't think you are.

Chris

[TG Twinkie]

I don't understand why you are getting readings so HIGH; the only thing I can think of is that since the only load you have on the charger is the meter and the meter being such high impedance, you are really not loading it down. If you have a 12 volt light fixture around that is in relatively good shape, even if it a tail light or marker light; just temporarily wire it up to one of the green wires that you know works. With the light working, measure the voltage, it will probably be in the 12 to 14 volt range with a load. Are you using a 24 volt charger? But the readings you are getting makes it sound like the wiring is good. Is this the same charger you used to check out the interior light? As for the short umbilical cord. You can splice into the existing cord; using "barrel" or "butt splice" connectors, they come in different sizes and take a crimping tool to install. The yellow ones are for #12 and #10 wire; blue is for #14 wire; red is for #16 wire. You can get these at auto parts stores, maybe even Wal Mart. Is there a Home Depot or Lowes any where close? You can also get what is known as "Heat Shrink Tubing" It must be large enough to go over the area you are splicing. Do your best to stagger the splices so you don't have a huge wad of splices all in one place. If you need pics of what I'm talking about, I can provide them.

[ck21084]

Originally Posted by TG Twinkie

I don't understand why you are getting readings so HIGH; the only thing I can think of is that since the only load you have on the charger is the meter and the meter being such high impedance, you are really not loading it down. If you have a 12 volt light fixture around that is in relatively good shape, even if it a tail light or marker light; just temporarily wire it up to one of the green wires that you know works. With the light working, measure the voltage, it will probably be in the 12 to 14 volt range with a load. Are you using a 24 volt charger? But the readings you are getting makes it sound like the wiring is good. Is this the same charger you used to check out the interior light? As for the short umbilical cord. You can splice into the existing cord; using "barrel" or "butt splice" connectors, they come in different sizes and take a crimping tool to install. The yellow ones are for #12 and #10 wire; blue is for #14 wire; red is for #16 wire. You can get these at auto parts stores, maybe even Wal Mart. Is there a Home Depot or Lowes any where close? You can also get what is known as "Heat Shrink Tubing" It must be large enough to go over the area you are splicing. Do your best to stagger the splices so you don't have a huge wad of splices all in one place. If you need pics of what I'm talking about, I can provide them.

Even unloaded 24volts would be much to high for a 12v charger the max that would be reasonable would be 14.8v.

[TG Twinkie]

Normally in a DC system the white wire is "ground" or "common" and it has a negative polarity; the different colored wires; black, red, yellow, green etc are the Hot wire(s) and they have a positive polarity. Each color is assigned to a specific circuit such as tail/marker lights (green); left turn (red) etc.

In an AC circuit normally used in a travel trailer there are 2 colors and a bare wire involved.

Black is the "HOT" wire and is usually connected to the circuit breakers in the panel and may be used in 120 volt light switches as the power (hot feed) to the switch. The "Black" wire is always connected to the gold screw on a duplex outlet or receptacle or other devices with screws.

White is the "NEUTRAL" and is always connected to the neutral buss (a row of screws that are on a metal bar in the panel). The "White" wire is always connected to the silver screw on a duplex outlet or receptacle or other devices with screws. It is also used in what is known as "Switch Legs" in circuits. I doubt you will have these unless you have 120 lights with a separate light switch like in your home. The neutral to buss should not be grounded to the power box or trailer.

The Bare wire is the AC "Ground" wire. (NOT TO BE CONFUSED WITH THE DC GROUND/COMMON WIRE). The AC ground wire is the "SAFETY" to keep you from being shocked and is connected to any metal box or device and the skin and/or frame of the trailer, also to any bare wire in an AC light fixture that is metal. It is also connected to the "GROUND BUSS" (IT LOOKS SIMILAR TO THE NEUTRAL BUSS BUT IT'S NOT) in the panel. DO NOT CONFUSE THE 2 BUSSES. The "Ground" buss is mechanically attached to the metal box that holds the circuit breakers and to the "ground wire" coming in from your "SHORE POWER" cord. There should also be a #6 or larger solid bare wire that connects to the ground buss at one end and to the trailer chassis/skin at the other.
Even though the "DC Ground or Common" wire and the "AC Ground" are both connected to the skin or chassis of the trailer; they serve very different purposes. The "DC Ground/Common" is the RETURN path for the DC circuit devices; since most only have one wire.
The "AC Ground" is just that; A Ground wire for Safety. No current will flow in the AC ground circuit under normal cicumstances.
The AC circuits are normally wired with "Romex" solid wire either #14 (15amp) or #12 (20amp) depending on the circuit breaker size; with the exception of the "SHORE POWER" cord.
The DC circuits are normally wired with "STRANDED" wire of different colors and wire guages depending on the load of the circuit and their assigned use.

NOTE: WHEN CONNECTING THE BATTERY IN YOUR TRUCK OR CAR RED IS POSITIVE AND BLACK IS NEGATIVE. IN THE TRAILER BLACK IS POSITIVE AND WHITE IS NEGATIVE. As I said in an earlier post "The automotive industry really made things confusing.
Hope this helps.

[Minno]

Originally Posted by lucymcdog

After taking loose all the outside lights on the trailer this is what I found:

Running lights on curbside - 1 green wire from trailer tied to 1 green light wire
Taillight - curbside - 1 black wire from trailer which was loose, 1 brown wire tied to 1 black light wire plus 2 green wires to 1 green light wire
Taillight - streetside - 1 red wire from trailer tied to black light wire and 2 green wires from trailer to 1 green light wire
Running lights on streetside - 2 green from trailer tied to 1 green light wire
License plate light - 2 green from trailer tied to 1 black wire which was then tied to 1 yellow wire which went to the light.

Is it hopeless?

Nope - not hopeless!

Running Lights: The green wires are all connected together inside the trailer walls (or they should be all connected together anyway), and they are the running lights. I would totally expect to see at least one green wire at each light location. When you replace the lights, make wire you keep the green wires connected together that are currently connected together. This should connect to the green wire in the stub of your umbilical cord.

License Plate Light: The color of the wire on the license plate fixture doesn’t really matter. It’s connected to the green running light wire coming out of the trailer – that’s what’s important.

Taillight Streetside: The red wire coming out of the trailer is for the streetside or left turn signal and brake light. The green wire is the running light. That’s also as I would expect. The red wire should connect to the red wire in your umbilical stub. And the green wire should connect to the other green wires.

The red wire also connects to a black wire on the fixture. That’s also normal as the taillight fixtures typically do not have red or brown wires on them. They usually have a green wire to show where the running light connection is, and then the other color wire is for the turn signal/brake light.

Taillight Curbside: The brown wire coming out of the trailer is for the curbside or right turn signal and brake light. The green wire is the running light. That’s also as I would expect. The brown wire should connect to the brown wire in your umbilical stub. And the green wire should connect to the other green wires.

I’m not sure what the black wire coming out of the trailer is for.

If you buy new lights, you may find that they also have a white wire. This will be the ground wire, and will be connected to the shell.

Chris

[TG Twinkie]

The black wire Chris mentioned may be to charge the battery. But check to see what color the brake wires are. Especially if you can't find a black wire inside the trailer; it should be a 10 guage wire if it is for the battery.

[lucymcdog]

I ran some tests on my multi-meter touching the probes and this is what I got:

2K position - .000
200 position - 00.0

I then touched the probes to each end of a 15' wire and got:

2K position - .000
200 position - 00.2

With the charger plugged in and not connected to anything except the probes on the meter (charger set at 2 amp) and the meter set in the 20VDC position I registered 10.71

THEN I connected the charger to a better place on the trailer for the ground with the black clip and put the red clip on the green wire from the umbilical cord. This is what I got:

Curb front green: 11.7

I then attached my new license plate light to the curb front green and grounded it to the trailer. The light worked.

With the light still attached, grounded and on, I checked out the other wires coming out.

Street front green - 8.6
Curb rear - 8.63
curb tail - 8.64
street tail - 8.62
Street rear - 8.62

Are those numbers ok? I don't know what I did differently other than have the ground clip in a better place and have a small light attached.

[lucymcdog]

I forgot to post a picture of my brake wire. It looks green in the picture but I think it is actually blue.

[Minno]

Originally Posted by lucymcdog

I ran some tests on my multi-meter touching the probes and this is what I got:

2K position - .000
200 position - 00.0

I then touched the probes to each end of a 15' wire and got:

2K position - .000
200 position - 00.2

With the charger plugged in and not connected to anything except the probes on the meter (charger set at 2 amp) and the meter set in the 20VDC position I registered 10.71

THEN I connected the charger to a better place on the trailer for the ground with the black clip and put the red clip on the green wire from the umbilical cord. This is what I got:

Curb front green: 11.7

I then attached my new license plate light to the curb front green and grounded it to the trailer. The light worked.

With the light still attached, grounded and on, I checked out the other wires coming out.

Street front green - 8.6
Curb rear - 8.63
curb tail - 8.64
street tail - 8.62
Street rear - 8.62

Are those numbers ok? I don't know what I did differently other than have the ground clip in a better place and have a small light attached.

Thanks for the info Lindy. When you were measuring the voltage on the wires, were you just measuring the green wires at each light location?

Chris

[Minno]

Originally Posted by lucymcdog

I forgot to post a picture of my brake wire. It looks green in the picture but I think it is actually blue.

Ok, that looks normal. One blue wire and one white wire inside a plastic covering. The blue wire should connect to the blue wire in your umbilical cord stub, and the white wire should connect to the white wire in your umbilical cord stub.

In the picture of your umbilical cord (copied below), where does the blue and white wire pair pointed to go? That looks like a brake wire as well. Maybe the other end of the wires you show in post 74?

[TG Twinkie]

The voltages you read (8.6 or there about) are low. It looks like voltage drop from Oxidation. When you install your new fixtures be sure to clean the ends of the wires coming out of the trailer; also make sure you have a good clean connection for the ground.
Did you connect the new license plate light to all of the locations around the trailer? I would just to make sure they are all OK.
You can also test the turn/brake light circuits and the tail lights as well as the license plate light position.
Make note for yourself to use in the future as to what color wires are for what device.
Sounds like your getting more comfortable using the meter.
Did you find the other end of the blue wire inside the trailer?

In the photo posted. Which wires go to the backplate of the brake assembly?
Where do the red wires go? To the other side of the trailer?

[lucymcdog]

Yes, I only measured the green. Forgot about the brown and red - I'll check those out tomorrow if I need to. The wire you pointed to is actually just a loose wire - black with a blue and white in it. That wire is 7' long and the other end of it isn't connected to anything. The end you see in the picture is bolted to the frame (white) and then the blue is tied into the cord that goes to the TV. It is not connected to the little blue stub in the umbilical cord coming from the trailer (between the brown and red)

[TG Twinkie]

Does the white wire that is in the sheath with the blue wire go to the frame of the trailer? You answered This question while I was typing.

Is there a connector on the other end of the umbilical cord?
.
Is the black wire with the blue and white inside long enough to reach the axle? Maybe it is part of the brake wiring. Does it look like it was connected at the far end to something at one time?
If it is not connected to the blue wire between the brown and red; What is it connected to? Does it look like it just came apart?
Did you find the other end of the black wire in the umbilical cord at another location in the trailer?
How many and what color wires are in the trailer umbilical cord? I see what looks like red, brown, white, black and green.
If that is the case:
Red=left turn/brake
Brown=right turn/brake
White=ground
Green=tail/marker and license plate.
Black=?? Battery Charge line from TV??
The umbilical cord to the TV looks like it has 7 conductors. Is that correct? If so: What colors are they?

[TG Twinkie]

There is no need for the blue wire that is in the black sheath along with the white to be connected to the trailer umbilical cord. It looks like it is connected to the TV umbilical cord; which is correct. If the black wire in the trailer UCord is for the trailer battery, that is where you will wire the breakaway switch to get power. The other wire on the breakaway switch will be connected to the blue wire that goes to the brakes.
Somewhere in the trailer there should be a white wire connected to the frame or skin. It is the other end of the white wire that is in the UCord. If you find that white wire I would bet there is a black one there as well.
I think the black wire from the TV UCord and the trailer UCord should be connected together.