How do I fix these lights in an RV?

[farmerjohn1324]

They are on DC power. The electrical equipment in the place is...

A circuit breaker, a converter to convert to DC, and a fuse panel.

All the rest of the lights in the place work and these lights worked just a week ago. It's not the bulbs because I checked them.

The only lights in the whole place that don't work are those two fixtures by the windows. They worked one week ago, then started flickering and would work sometime. Now, they don't work at all. What should I check first?

 

[MrModify]

How electrical savvy are you?

 

[farmerjohn1324]

How electrical savvy are you?

I know some basics. I'm not going to claim to be an expert. I went in there today thinking it was probably a blown fuse, but I checked them all and all the fuses were working (I looked at them and saw that they were not broken).

Also, I turned off the circuit breaker and was amazed to see that all the DC lights in the home still worked. I thought that the circuit breaker would turn off everything DC, but apparently not.

I plan on calling an electrician, but I would like to avoid that if possible.

I would like to find out if it is the fixtures that broke, even though I don't see why two of them would break at the same time... but since I apparently don't know how to turn the power off to the DC lights in the home, I don't know how I can safely do that.

 

[MrModify]

Can you check the two fixtures for corrosion where the bulbs make connection to the fixture. It is possible that the two fixtures are in series, This means that it is possible to have one fixture with a issue which will make both fixtures not work. Remove the bulbs and either ohm them if you have a Volt/ohm meter or place them in a know working fixture. Think simple. Next take the fixture down and see how the wiring looks behind the fixture. Let se what you find.

 

[farmerjohn1324]

The bulbs work. I checked them in other fixtures. I would take the fixtures down, but I don't know how to turn off the DC power. Even when I turn off the power to the whole unit, the DC power is still on.

 

[MrModify]

Is there a battery involved? Can you kill the whold system? Do you have a owner manual that maybe by chance there is a schematic?

 

[farmerjohn1324]

Is there a battery involved? Can you kill the whold system? Do you have a owner manual that maybe by chance there is a schematic?

No, all the DC power comes from a converter that I think comes after the circuit breaker in line from the electric poles. This is why I'm confused as to why the DC power is still on after turning off all the switches on the circuit breaker. I don't feel safe taking off the fixtures due to risk of shock.

 

[MrModify]

Is this a class A, B, C, motor home or is this a trailer?

 

[MrModify]

Are you in the USA ?
I ask because if it is a class a, b, or c motor home there is usually a second battery somewhere. The batteries get there charge from the alternator on the engine. There Is usually a battery isolator that keeps the engine battery from being discharged from the use of the rear battery.

Power should be from the pole to the breaker box (AC) to the invertor (DC) a battery tie if there is one then to fuse panel then to a switch then to bulbs.

pic IMG_20160123_242122476.JPG
You might want to try disconnecting the engine battery along with turning the main breakers off and see if this kills all the power.

I would think there has to be a way to shut down the AC power to the invertor. It may be the blue switched breaker.

DC is not like AC. I have no problem working on DC when it is live. I do with AC. I am not telling you to work it hot if you are not comfortable with that.

The ac comes in and feeds the invertor and probably the air conditioning units. The battery is going to tie in between the invertor and the lights.

pic IMG_20160123_242110190.JPG
Have you removed all the fuses to see what happens? If you do be careful they could be AC voltage.

If you can take a volt meter set to >120 vac and measure with one lead on the larger silver lug with the two larger black wires and the other lead going to the buss with all the white connected to it and let e know what you get.

The fuse panel could be either AC or DC. My guess is it is DC. It could also be both on the same panel.

 

[farmerjohn1324]

Are you in the USA ?
I ask because if it is a class a, b, or c motor home there is usually a second battery somewhere. The batteries get there charge from the alternator on the engine. There Is usually a battery isolator that keeps the engine battery from being discharged from the use of the rear battery.

Power should be from the pole to the breaker box (AC) to the invertor (DC) a battery tie if there is one then to fuse panel then to a switch then to bulbs.

pic IMG_20160123_242122476.JPG
You might want to try disconnecting the engine battery along with turning the main breakers off and see if this kills all the power.

I would think there has to be a way to shut down the AC power to the invertor. It may be the blue switched breaker.

DC is not like AC. I have no problem working on DC when it is live. I do with AC. I am not telling you to work it hot if you are not comfortable with that.

The ac comes in and feeds the invertor and probably the air conditioning units. The battery is going to tie in between the invertor and the lights.

pic IMG_20160123_242110190.JPG
Have you removed all the fuses to see what happens? If you do be careful they could be AC voltage.

If you can take a volt meter set to >120 vac and measure with one lead on the larger silver lug with the two larger black wires and the other lead going to the buss with all the white connected to it and let e know what you get.

The fuse panel could be either AC or DC. My guess is it is DC. It could also be both on the same panel.

It is a travel trailer (fifth wheel). There is no engine. The fuse panel is all DC. I will gladly work on hot DC as long as it won't hurt me.

 

[MrModify]

Everyone is different, I won't say it won't hurt you. I have been electrocuted by 12vdc system. Also with 120vac. Neither is fun but dc will tingle at low voltage. AC flat hurts.
Both can kill if the current goes across your heart! A couple of rules I was taught many years ago. If you are going to work a hot system keep one hand in your pocket at all times. Use STAR - stop - think - act - and review! Pay attention to where you are standing and what you are leaning against and is it wet. Any heart issues leave electricity alone.

At some point you will have to work with the power on to troubleshoot unless you have a volt/ohm meter.

Have you pulled all the fuses and turned all the breakers?

 

[farmerjohn1324]

Everyone is different, I won't say it won't hurt you. I have been electrocuted by 12vdc system. Also with 120vac. Neither is fun but dc will tingle at low voltage. AC flat hurts.
Both can kill if the current goes across your heart! A couple of rules I was taught many years ago. If you are going to work a hot system keep one hand in your pocket at all times. Use STAR - stop - think - act - and review! Pay attention to where you are standing and what you are leaning against and is it wet. Any heart issues leave electricity alone.

At some point you will have to work with the power on to troubleshoot unless you have a volt/ohm meter.

Have you pulled all the fuses and turned all the breakers?

Thanks for the help.

I am not interested in getting injured. I heard the converter crackle when I moved in and that was enough to scare me.

Do you know why the DC power won't turn off when the circuit breaker switches are all off? I don't think there is a battery. I don't know where it would be if there was one.

I have a circuit tester and will buy a volt-ohm meter if necessary. The type of tester I have had a sharp point and two clamps, with no digital display.

Are you saying that I should remove all the fuses in order to turn off the DC power? (Even if that would work, I would still like to know why it is on in the first place when all the AC has been turned off)

And if I take those fixtures down, how exactly do I test them?

 

[farmerjohn1324]

Everyone is different, I won't say it won't hurt you. I have been electrocuted by 12vdc system. Also with 120vac. Neither is fun but dc will tingle at low voltage. AC flat hurts.
Both can kill if the current goes across your heart! A couple of rules I was taught many years ago. If you are going to work a hot system keep one hand in your pocket at all times. Use STAR - stop - think - act - and review! Pay attention to where you are standing and what you are leaning against and is it wet. Any heart issues leave electricity alone.

At some point you will have to work with the power on to troubleshoot unless you have a volt/ohm meter.

Have you pulled all the fuses and turned all the breakers?

I figured out how to turn off the DC power. It was the blue switch on the circuit breaker. There was current stored up, so the lights stayed on for a while before they turned off.

I tested all four bulbs in working fixtures and the bulbs are fine.

I don't see any corrosion where the bulbs connect to the fixture, but I attached pictures of all four. Do you see corrosion?

When I unscrew the 8 screws that attach the fixture to the wall, I can't take the fixtures off because the wires prevent me from taking it off. I can get them down far enough to see 5 wires.

Two white wires that go to each bulb from the ceiling. A black wire from each bulb to the switch, and a black wire from the ceiling to the switch. (is this the ground?)...

From what I see, they all seem to be connected properly.

What do you think I should try next?

 

[MrModify]

I figured out how to turn off the DC power. It was the blue switch on the circuit breaker. There was current stored up, so the lights stayed on for a while before they turned off.

That's good. I had thought about that. But if it took sometime to bleed down there is a battery somewhere.

I don't see any corrosion where the bulbs connect to the fixture, but I attached pictures of all four. Do you see corrosion?

No I don't.

Two white wires that go to each bulb from the ceiling. A black wire from each bulb to the switch, and a black wire from the ceiling to the switch. (is this the ground?)...

The two white wires should be negative/ground and the black should be positive/hot.

From what I see, they all seem to be connected properly.

It is. I suspect the switch.

The type of tester I have had a sharp point and two clamps, with no digital display.

Can you send pic of your tester? I don't under stand the 2 clamps. The switch can be tested with a volt ohm meter with no power on switch. Or you can test switch with the power on with the tester you have but I need pic first to see what you have.
If you chose and live in the US and you have a Harbor Freight nearby they sell a cheap volt ohm meter which is great for what you are doing.

 

[farmerjohn1324]

I figured out how to turn off the DC power. It was the blue switch on the circuit breaker. There was current stored up, so the lights stayed on for a while before they turned off.

That's good. I had thought about that. But if it took sometime to bleed down there is a battery somewhere.

I don't see any corrosion where the bulbs connect to the fixture, but I attached pictures of all four. Do you see corrosion?

No I don't.

Two white wires that go to each bulb from the ceiling. A black wire from each bulb to the switch, and a black wire from the ceiling to the switch. (is this the ground?)...

The two white wires should be negative/ground and the black should be positive/hot.

From what I see, they all seem to be connected properly.

It is. I suspect the switch.

The type of tester I have had a sharp point and two clamps, with no digital display.

Can you send pic of your tester? I don't under stand the 2 clamps. The switch can be tested with a volt ohm meter with no power on switch. Or you can test switch with the power on with the tester you have but I need pic first to see what you have.
If you chose and live in the US and you have a Harbor Freight nearby they sell a cheap volt ohm meter which is great for what you are doing.

I can go to the store and get a volt-ohm meter right now if I have to.

One clamp on my tester. I wasn't around it when I said that. My memory wasn't accurate.

I attached a picture of the inside. The bottom left is the door where the circuit breaker, converter, and fuse box are.

In the very top right, you can barely see one of the fixtures and in the middle on the top is the other one. Which is more likely to be first in line, and thus the cause of this problem? Or do you have enough information to tell? I can take more pictures if necessary.

If it is a switch, will it be necessary to replace the whole fixture?

 

[MrModify]

Ok I'm confused. You have two separate fixtures with each fixture having two bulbs?
So total you have 2 fixtures 4 bulbs?

 

[farmerjohn1324]

Ok I'm confused. You have two separate fixtures with each fixture having two bulbs?
So total you have 2 fixtures 4 bulbs?

Correct.

And I'm assuming they are in line and that the fixture first in line is responsible for the problem.

 

[MrModify]

Ok that changes things a bit. For now scratch the switch.

Have you removed fixtures enough to get to wires on both fixtures?

If so are the pictures of the wires posted? If not please post pics?

Can you get a pic of the switch on either fixture? If so please post.

 

[farmerjohn1324]

Ok that changes things a bit. For now scratch the switch.
Have you removed fixtures enough to get to wires on both fixtures?
If so are the pictures of the wires posted?

Yes, and here it is again.

This is one. The other one, I can't pull down as much because it feels like the wire is about to break if I pull any more.

 

[MrModify]

Is the other light fixture wiring the same? 1 white wire to two white wires and one black wire.
Picture of wire side of switch?

Sorry for all the questions but it helps me to tell how to handle it. We are getting close to testing.