Marker Lights; how to make them 'switchable?'

[burlesot]

All,

Thanks in advance from a very newbee electrical system designer. Here is what I want to do:

I'm installing two 'porch lights' (red led's) over the doors on my teardrop. I'm thinking that it would be cool to tie into the marker lights (red and orange lights at front and back) so that when I turn on the porch lights, the marker lights come on too.

The marker lights will be on the wire harness from the car. Am I making something much more complicated than it need be? Should I just avoid trying to 'tie into' this?

Thank you,
Todd

[goldcoop]

Sounds like a job for:

http://www.rvglow.com/

Cheers,

Coop

[burlesot]

I don't have a seven way switch....

So the RV Glow won't work for me; guess I'm the 1%

[Socal Tom]

There are probably better ways to do it, but here is what I would do.

Tie the lights into the marker circuit, but install a switch where it makes sense ( switch will be turned on when towing).
Run a power line from the battery to the front of the trailer, and run the power to a female version of your trailer plug) Determine which wire ( probably brown) is for the marker lights, and run the battery power to that wire two sections of the plug).

When towing, the marker lights will come on with the headlights as long as you are plugged into the TV( as long as the switches are on).

When parked, connect the female end you just installed to power the marker light circuit ( the tail lights will also come on unless you put a switch on them as well).

Tom

[burlesot]

SoCal,
I think I need a diagram for that.

However, thinking a bit on your idea. Are you basically saying that you could by-pass the marker lights (which are usually powered by the tow vehicle's battery) and instead power them from the teardrop's battery while towing? You would have to flip the switch on in/on the teardrop to have the marker and porch lights light up during towing?

I would, of course, have a line from the alternator/battery charging the teardrop's battery while driving, so I guess it's basically the same thing, right? Am I making this too simple?

Thank you,
Todd

[halfdome, Danny]

All,

Thanks in advance from a very newbee electrical system designer. Here is what I want to do:

I'm installing two 'porch lights' (red led's) over the doors on my teardrop. I'm thinking that it would be cool to tie into the marker lights (red and orange lights at front and back) so that when I turn on the porch lights, the marker lights come on too.

The marker lights will be on the wire harness from the car. Am I making something much more complicated than it need be? Should I just avoid trying to 'tie into' this?

Thank you,
Todd

Todd, If I understand you correctly you want to have decorative lighting when camping and maybe unhitched from the tow vehicle.
I have a switch that the power & ground is supplied from the teardrop battery.
I tapped into the closest clearance light positive wire only.
If you use the clearance lights ground you won't be able to turn off your teardrop negative battery kill switch, I know this as it happened to me.
If you keep the wire harness from the tow vehicle plugged to the teardrop it will make the tow vehicle clearance lights light up and the warning chime will sound off.
Danny

[burlesot]

Slow,

I 'could' have the porch light on when towing; it's a Red 3 LED fixture. Would just be like another marker light, right?

Halfdome, I understand what you mean about using the ground from the teardrop battery; that keeps it in the teardrop's power system. You are saying though that you only needed to tap into the positive terminal of the marker lights, right?

Thanks for the advice.

I'm kinda in over my head with this and appreciate the insights. Silly, but pictures help my mind make sense of it. I'm a very visual learner.

Thanks,
Todd

[goldcoop]

Todd-

Let's establish what car/trailer connector you have, i.e. flat 4, round 5, etc. ?

What is your 12v power source in the teardrop, i.e. battery, converter, power supply, etc.?

Do you ALWAYS disconnect the trailer from the car (at least the wiring between the two)?

Does this need to be "idiot proof" i.e. will you be lending it out to others to use?

Answers to these would help to "design" what you are trying to do...

It could be done with a 3-way switch in the clearance light circuit from the lights to either the 12v trailer source or the car/trailer connection, you are going to have to make sure you always have it switched correctly...

Another thought is make an "extension cord" of just the clearance light circuit from the 12v trailer source to the trailer plug connection and simply plug that in when it gets dark.

Cheers,

Coop

[Dale M.]

Absolute easiest way to make driving markers come on with porch lights would be to just add wiring from 12 volt source inside trailer that powers porch lights and control them from porch light switch.... However you may (will) need BLOCKING (isolation) diodes so porch lights are not on when in tow mode (clearance lights only for trailer) or so you do not feed back to TV with power from trailer to TV lights while parked but still connected.....

http://www.the12volt.com/diodes/diodes.asp

Porch-marker lamps.JPG (28.91 KiB) Viewed 935 times

Dale

[desertmoose]

Easier with pictures, but I'll try to describe the best way (In my opinion) to do this.

Get a single pole double throw switch.

Bring in power from the trailer plug to the LH contact.
Bring in power from your 12v battery to the RH contact.
Hook the center contact to your lights. (power in)

With the switch flipped one way, the power will come from the trailer plug and go to the lights. The lights will come on with the running lights
Throw the switch the other way, and the power will come from the 12v battery and go to the lights. The lights will stay on as long as the battery lasts.

If you need a diagram, I can try to get one together.

Sam

[Socal Tom]

SoCal,
I think I need a diagram for that.

However, thinking a bit on your idea. Are you basically saying that you could by-pass the marker lights (which are usually powered by the tow vehicle's battery) and instead power them from the teardrop's battery while towing? You would have to flip the switch on in/on the teardrop to have the marker and porch lights light up during towing?

No, when driving you would plug into the car just as you do now.

I would, of course, have a line from the alternator/battery charging the teardrop's battery while driving, so I guess it's basically the same thing, right? Am I making this too simple?

Thank you,
Todd

You are 1/2 way there. If you take the charge wire you have now, and connect it to a copy of the tow connector on the back of your car, you just plug the Tear drop ( male) end into the female connector that gets power from the tear drop battery once you park. The switches are so that you can turn off the marker lights during the day or what not.

Here is a very poorly drawn schematic assuming you are using the "flat four" connector.

[burlesot]

Thank you guys!

Just to answer the questions from SoCal.

I have a four way, flat plug from my tow vehicle.

The power source in my teardrop is 12 volt battery.

I will NOT be lending the teardrop to others, so the only idiot is me.

I'm going to need to study these diagrams to think about what they mean.

Thanks guys,
Todd

[burlesot]

Dale,
I'm not familiar at all with a blocking diode.
Can you put that in layman's terms?

I really appreciate all of the posts trying to help.

I especially appreciate your patience with my ignorance.

Someone quite wise reminded me that we all are learning.

T

[jss06]

Dale,
I'm not familiar at all with a blocking diode.
Can you put that in layman's terms?

I really appreciate all of the posts trying to help.

I especially appreciate your patience with my ignorance.

Someone quite wise reminded me that we all are learning.

T

The blocking diode allows electricity to flow only in one direction. In this case it is the direction the arrow is pointing and stops electricity from flowing through the porch lights except when the light switch is on. In the diagram, think of the diode as a one way valve. As long as electricity is flowing in the direction the arrow is pointing, the ciruit works like a copper wire. If electricity tries to go in the opposite direction, the diode acts just like a wall to keep it from going that way.

[milliejohn]

just add another set of marker lights and wire them to your porch light, then you have complete isolation between towing and trailer lights, and if you go LED on these new lights, you'll never burn out a bulb. Not the only way, but an easy alternative to a complicated question.