CTH reset - High Country Cargo Toy Hauler Conversion

[Itsdoable]

I'll get some detailed pics of the bed tomorrow. Snowed here today, but did get the Wave heater in.

I have an electrical problem that needs some advice. When I ground the battery to the chassis, the outside lights come on. The switch for these lights does nothing. The amp meter shows no load. Pull the fuse, no lights. Remove the battery to chassis ground and everything works fine (switch, load, etc.) They are on a unique circuit. All other circuits are OK. Do I have a hot wire in that circuit which is grounding on the chassis (after the fuse box, but before the switch)?

[pete42]

do the lights work with just the truck hooked up?
I take it you are talking about your trailer batteries ground wire.
is this a new problem or an ongoing one?
what is the last thing you did before the problem?
does the trailer battery and the tow battery go to the same ground?
One thing to try is removing the bulbs one at a time from their sockets to see if the problem goes away after you eliminate easier things.
on your battery switch which wire did you break hot or ground?
wished you lived close by I miss fixing these kind of things
a wiring diagram hand drawn would help a lot.
Pete

[Itsdoable]

do the lights work with just the truck hooked up?
Truck is not hooked up to the trailer 12V system, yet.

I take it you are talking about your trailer batteries ground wire.
Yes, 12V trailer battery

is this a new problem or an ongoing one?
new since I grounded battery to chassis today

what is the last thing you did before the problem?
grounded battery to chassis

does the trailer battery and the tow battery go to the same ground?
no tow battery hooked up

One thing to try is removing the bulbs one at a time from their sockets to see if the problem goes away after you eliminate easier things.
on your battery switch which wire did you break hot or ground?
hot

wished you lived close by I miss fixing these kind of things
a wiring diagram hand drawn would help a lot.
Pete

My trailer is all 12V running off a battery (except taillights etc.), with a 120A charger. These are outside lights I added. With the battery not grounded to the chassis, everything works fine.

With battery grounded to chassis the outside lights stay on all the time if; 1) on/off switch is on, 2) fuse for that circuit is in. Light switches do not work when grounded to chassis. Amp meter shows no draw. If I turn off the on/off or pull the fuse for that circuit the outside lights go off. Other circuits appear fine.

[Itsdoable]

As you can see, I'm not an Electrician, hopefully this makes sense. Thanks for the help !

[Jo]

Your outside lights that you have installed, have a separate ground wire that go back to the "neg" of your battery or you're using the Chassis as a ground for these lights?

If you're using the chassis as a ground for the lights, it look like the lights have power (12Vdc) even if the switch is OFF.

In other words, is it wired as A or B?

[Itsdoable]

Your outside lights that you have installed, have a separate ground wire that go back to the "neg" of your battery or you're using the Chassis as a ground for these lights?

If you're using the chassis as a ground for the lights, it look like the lights have power (12Vdc) even if the switch is OFF.

In other words, is it wired as A or B?

The intent is all grounds come back to the fuse box, like 'A'. But, you got me thinking and it looks like the fixtures could be unintentionally grounded to the skin/chassis. I hate electrical problems

[Itsdoable]

OK, here is the circuit as I believe it stands now.

[Itsdoable]

You guys are going to get tired of me ...

Did a little experiment. With the Battery ground-to-chassis unhooked, I turned on one or the other of the light switches shown in the above drawing. Didn't matter which switch I used, all 3 outside lights came on.

What I think this is telling me is when power is getting to one of the fixtures it's electrifying the chassis. I believe this is caused by the fixture's rivet/screws.

Do you agree?

How do I fix it? Replace the fixtures with something other than $4 units that ground to the trailer skin?

Thinking out loud ...

Or maybe not worry about outside lights at all, because the trailer will probably glow in the dark anyway!

[Jo]

First of all, grounding the Negative of the battery and the fixtures to chassis is OK.

Are you sure that the polarity is correct? If you did not connect them properly and the negative is now positive that can make sense.

Do you have to activate a switch for the lights to come ON or as soon as you hook the battery your lights go ON?

[Itsdoable]

First of all, grounding the Negative of the battery and the fixtures to chassis is OK.

Are you sure that the polarity is correct? If you did not connect them properly and the negative is now positive that can make sense.

Black/hot, white/negative. I could have hooked one up incorrectly ..

Do you have to activate a switch for the lights to come ON or as soon as you hook the battery your lights go ON?

With battery grounded to chassis, all lights come on and stay on regardless of light switch/s position.

With battery ungrounded to chassis, one or other switch must be on for the 3 lights to come on.

[pete42]

Your outside lights that you have installed, have a separate ground wire that go back to the "neg" of your battery or you're using the Chassis as a ground for these lights?

If you're using the chassis as a ground for the lights, it look like the lights have power (12Vdc) even if the switch is OFF.

In other words, is it wired as A or B?

Jo with the light switch off I think either way the lights should not light unless it is backfeeding through the amp/volt meter.

itsdoable looking at your picture of the light I would say that the light fixtures are indeed grounded to the chassis.
did the lights come on bright or dim?
if dim then something is wired in series and the lights are not seeing 12 volts due to voltage drop across the bulbs.
you may have to not ground the battery just use a floating ground to the light circuits.
what this will do when you hook up uour truck and plug in trailer will be fun to see what happens.

[pete42]

sorry Jo I was to slow in responding I too think either he wired them wrong (it happens) or one of the sockets or pulgs are made wrong again it happens turning on one light switch and having all lights come on means they are in series.
another thought if the lights all come on bright then you have the switches wired in parallel.

[Jo]

One good news Itsdoable!

It's impossible that you "electrified" the chassis with the 12Vdc, because when you ground the "Neg" of the battery you're not seeing a Welder Arc.

If you switched the "+" and the "-" in the fuse box or somewhere else that could make sense.

Can you check the polarity with a Voltmeter?

[Itsdoable]

Lights appear same brightness regardless of senario.

Experiment #2.

Removed all 3 fixtures and insulated the units from the trailer, still wired up.

Everything works perfectly, regardless if the battery-to-chassis ground is hooked up or not. Switches work as planned, only turning on the intended lights.

Symptoms are eliminated, but given Jo's comments, I'm not confident I know the cause.

What to do next ? (BTW, you're getting over my head with "check polarity with voltmeter")

Leaving for Moab in 3 days and I don't want to be arching at passing cars on the way.

[Jo]

Do you have a voltmeter?

Listen to this video, it's pretty simple:
http://www.youtube.com/watch?v=tc8rkOYWZuE