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Greg1410 · 08-19-2016, 09:32 AM

My electrical skills are a bit lacking. My trailer is gutted so I have access to all wiring. I would like to put a switch inside to turn the clearance lights off and on when parked and not hitched up. I've read where people have turned on their clearance lights by using jumpers in the umbilical cord, but I would like to put a switch inside the trailer. I am thinking this should be easy. I believe I would just splice a wire anywhere along the circuit of the clearance lights and run it to the 12V dc distribution box and put the switch somewhere between the splice and the box. Is this correct? Would this interfere with the function of the clearance lights while towing at all?
Thank you,
Greg

Protagonist · 08-19-2016, 10:01 AM

Quote:

Originally Posted by Greg1410

I would like to put a switch inside to turn the clearance lights off and on when parked and not hitched up. I've read where people have turned on their clearance lights by using jumpers in the umbilical cord, but I would like to put a switch inside the trailer. I am thinking this should be easy. I believe I would just splice a wire anywhere along the circuit of the clearance lights and run it to the 12V dc distribution box and put the switch somewhere between the splice and the box. Is this correct? Would this interfere with the function of the clearance lights while towing at all?

The best way would be to use a blocking diode to provide power to the clearance lights from two different sources. That way, when towing you're not back-feeding power to the house 12v system. The diode becomes your splice, with two inputs from house electric and umbilical, and one output to the lights.

Blocking diodes are also used when wiring supplemental lights for a toad to allow taillights, turn signals, etc to be powered by the towing vehicle's umbilical cable or by the toad's own electrical system, which is how I know about them.

Greg1410 · 08-19-2016, 10:33 AM

Thanks Protagonist - makes sense.

I googled 12V DC blocking diodes to learn more and find a source - could not really find anything - can you recommend a good source and size?
Thanks,
Greg

jdalrymple · 08-19-2016, 10:40 AM

As Protag has mentioned, the problem with simply adding a switch to the circuit is that the power the switch is adding to the circuit will flow to umbilical as well as the lights.

This could be a problem if the umbilical is shorted against something or plugged into the vehicle.

Another way to solve the back feed issue, instead of a blocking diode, would be to install a double throw switch.

One would install the switch inside and run the light wire from the umbilical to said switch, a power wire from the 12 volt system of the trailer, and connect the center pole to the lights.

This would allow the choice of powering the lights from the umbilical or the 12 volt system.

Regards,

JD

ROBERT CROSS · 08-19-2016, 10:50 AM

.......for our 63 Safari.

Got a spare female 7way plug, jumped 12v to the running light pin. Just plugged it in when we felt kool. (I suppose I could have put a switch/fuse there)

Bob

jimfa440 · 08-19-2016, 11:19 AM

Searching for a "blocking diode" is like searching for "wet water line". All diodes are blocking, that's what they do. Simply look for a diode with the appropriate power rating. As for me, I use a plug like the one on my TV and strap the running light terminal to the battery terminal. When I park, I plug it in.

64airstream · 08-19-2016, 11:28 AM

I have not installed a switch, but I've thought about it. I have on "cool" occasions put a short piece of wire (jumper) between the 11 O'clock and 1 O'clock connectors (the one on each side of the alignment tab) of the 7 pin trailer plug. My thought was to simply permanently install the same jumper, but with a switch and with its wires run inside to wherever I wanted the switch. Since you'd want the plug disconnected from the tow vehicle when using the switch, this would not be fail-safe, like Pro's solution.
So, I just stick with the jumper, that way the plug is disconnected to get to the contacts. (At least for now, while I can still remember that I have a poor memory...)

Roy

Jaxon · 08-19-2016, 11:42 AM

Quote:

Originally Posted by 64airstream

I have not installed a switch, but I've thought about it. I have on "cool" occasions put a short piece of wire (jumper) between the 11 O'clock and 1 O'clock connectors (the one on each side of the alignment tab) of the 7 pin trailer plug.
Roy

.
Do the same thing but using a 10amp automotive fuse plugged in at the 11 & 1 o’clock positions...
.

cazual6 · 08-19-2016, 11:49 AM

You can also check out, a double pull double throw switch. This will ensure you don't have to worry about any back feed.

Greg1410 · 08-19-2016, 12:11 PM

JD:

Thanks for the note - I like the switch idea.

Would this be an SPDT switch? I would splice the switch in between the umbilical and the first clearance light I assume. Also, my clearance lights are grounded where they are at - to the shell; so I assume I would not need an additional ground wire, correct? So when I am driving, the switch would allow power from the umbilical, and when when camped, I can flip the switch to turn them on. If I am disconnected from my TV and want the lights off, i would switch them back to the umbilical I assume.
Sound correct?
Thanks,
Greg

jdalrymple · 08-19-2016, 12:21 PM

Quote:

Originally Posted by Greg1410

JD:

Thanks for the note - I like the switch idea.

Would this be an SPDT switch? I would splice the switch in between the umbilical and the first clearance light I assume. Also, my clearance lights are grounded where they are at - to the shell; so I assume I would not need an additional ground wire, correct? So when I am driving, the switch would allow power from the umbilical, and when when camped, I can flip the switch to turn them on. If I am disconnected from my TV and want the lights off, i would switch them back to the umbilical I assume.
Sound correct?
Thanks,
Greg

Yes, SPDT switch.

No change to grounding, as the shell serves as the negative connection for both the 12 volt system in the trailer as well as the tow vehicle.

When parked with umbilical unplugged, the switch would simply function as an on/off as there would be no power applied via the tow vehicle.

Sounds like you see the light............

Regards,

JD

cwf · 08-19-2016, 12:23 PM

Well, what little I know about electricity, would be shocking. Be forewarned...

What follows is a "hold my beer and watch this" moment.

For starters, this what I would use to test the theory while the "inner walls" are accessible.

Perhaps it would be a good idea to build a "project box" which you mount the components and wiring... And place where you have access... I case of failure... This way you can add a mounted fuse for easy replacement if needed.

They may sell all those parts on the website, but here is diode link...

http://www.allelectronics.com/make-a...diode-5/1.html

featherbedder · 08-19-2016, 05:34 PM

Putting swt. for clearance lights just 1 more thing to go wrong or forget to turn off. Just use 10 amp fuze in umbilical cord at 11 & 1 o'clock position, SAFER than SWT. and no worry of back feed or miswiring or complicated wiring. Also less than1$.

TG Twinkie · 08-19-2016, 05:38 PM

I am with Robert Cross. Simple and you can't forget to turn it off.

mrfixit51 · 08-20-2016, 11:36 AM

Hi
If you have a hitch battery box, how about putting another female 7 pin socket on the hitch box. In other words ,your trailer whip will have 2 males. Then put a simple toggle next to it. When parked just flip the switch. Use an inline fuse for protection. That is the way i have set up my vintage travelux. See attached pictures. Hope this helps. Take care

HiJoeSilver · 08-20-2016, 07:02 PM

If you want to use a switch it's pretty easy. Get a 12v on-on switch. They have them for rv lights etc, common at rv dealer parts departments. Also VTS has them. They have 3 prongs on back center prong is the load, in this case feeding to the running lights. The other two prongs are the suply voltage wires. In this case you would connect one to the wire from the umbilicle the other to a 12v supply from the trailer. When the switch is on one position it will power from umbilicle, switched the other way 12v from trailer. Can't be both at same time so no back feed worries.

drboyd · 08-20-2016, 08:16 PM

Buy yourself a remote switch off ebay, and connect it to a female connector. Just connect 4 wires, plug it in and push the button.

mrfixit51 · 08-21-2016, 06:13 AM

thanks hijoe silver, you are right . Got to protect the feedback. A 3 position is necessary.

Protagonist · 08-21-2016, 06:33 AM

Quote:

Originally Posted by HiJoeSilver

If you want to use a switch it's pretty easy. Get a 12v on-on switch. They have them for rv lights etc, common at rv dealer parts departments.

That type of switch works.

The main reason I recommended a blocking diode instead is that with the diode, you can't forget to switch on the clearance lights when you plug in the umbilical cable; they come on automatically. A blocking diode combined with a simple on/off switch only on the house side lets you choose whether to turn the clearance lights on when camping, but always have them on when the tow vehicle's lights are on.

ROBERT CROSS · 08-21-2016, 06:43 AM

Quote:

Originally Posted by ROBERT CROSS

.......for our 63 Safari.

Got a spare female 7way plug, jumped 12v to the running light pin. Just plugged it in when we felt kool. (I suppose I could have put a switch/fuse there)

Bob

FWIW......since getting the Classic I no longer feel the need to be

, so the running lights only run at night while running down the road.

Bob