Installing a third stop light

[Bruce and Jenna]

Rockin' - Do not Read This!

I want to install a third stop light on the back of the trailer, like on newer cars. This one


About here

I figures to solder wires onto the ends of the light leads, and connect them to the corresponding leads on that stop light in the lower right. (Assuming I have popped the correct light out of the two.)

I measure about 30" diagonal between the mount point and the hole for the existing light.

The wall has fiberglass insulation in it. I don't want to drill too big a hole in the fiberglass.

-What is the best way to snag the wires?
-And do you have any suggestions or warnings about drilling and sealing that hole?

"RVers rush in where homeowners fear to tread."

PS Rockin' - I told you not to read this!

[Chuck 1935]

Have you thought about the right stop light will also activate when you turn on you right hand blinkers. To avoid this you will have to have input from both stop/turn lights and put diodes in the line to seperate the two.

[Ray,IN]

Chuck is right. If you still want to do this:
You will need stiff, but easily bent wire to fish the 12V wires through the insulation. I suggest buying a small roll of black rebar tie wire. It is in a coil but may be easily straightened by hand. A 3/8" hole in the fiberglass should be large enough to work with. Once you are sure of exactly where you wish to drill the hole, I would use a better quality wall stud-finder to find any obstructions in the path of the proposed wiring. May not be a 100% way to find any, but it beats finding them with the wire_after you have drilled a hole.
If that goes as planned, and you do not find any obstruction, it's time to drill. Push the black rebar wire through to the existing stoplight wire hole. It will probably take some time to locate the rebar wire end and get it through the hole you may secure the 12V wires to it.
That would be my way of adding a light to the outside of my RV. If you find obstructions inside the wall, the only option is to run the 12V wiring straight down then across under the RV to the present stop light, then straight up.
Sealing wiring holes; seal the wiring holes using butyl tape, dicor non-sag sealant, or Eternabond tape. This way, any water that may find its way into the light fixture cannot follow the wires into the RV wall.
Hope this idea has merit!

[Still Working "NOT"]

Bruce,

Have fun with this project. After many years of trying to fish walls make sure you have lots of time to do this. The problem will be the insulation in the wall. It will make fishing to the location you want real hard to get to. I would try to shove a metal fish tape from the existing tail light in the general direction you want to end up at. Take a magnet stud finder and see it will pickup the fish tape. You may have a problem with a stud in the wall by the existing light that will interfer with you having a clear shot towards the location where you want to place the new light.

They make a bit for drilling a hole through the studs. You can get it at Home Depot or Lowe's. It is costly if I remember. $40 or there about. You might also have a stud in the center of the location also. If you can get the drill bit to the location Drill your hole in the wall for the wiring.

The other choice will be place the wiring inside your rig in the cabinets if you have any there.

Hope this helps.

SKIA Jr.
AKA Larry

[Bruce and Jenna]

Quote:

Originally Posted by Chuck 1935 Have you thought about the right stop light will also activate when you turn on you right hand blinkers. To avoid this you will have to have input from both stop/turn lights and put diodes in the line to seperate the two.

The existing stop light has separate wires for Stop and Turn, as well as Ground. The new one has wires labeled the same. So I assumed that I could connect the Stop wire from the new light to the Stop wire from the old light. No?

Could I attach long wires to the new light, maybe wrapped around large nuts for weight? Then push my fish tape horizontally toward the wire to snag 'em? Rather than trying to find the hole?

Quote:

Originally Posted by Ray, IN If you find obstructions inside the wall, the only option is to run the 12V wiring straight down then across under the RV to the present stop light, then straight up.

Yeah, if I find studs, I could run the wire straight down. I could connect to a set of wires under the corner of the bumper for a trailer connection. Heck, I might just choose this anyway, if I can't easily catch my fish.

Quote:

Originally Posted by Still Working "NOT" SKIA Jr. AKA Larry

Don't piss him off. He who holds the booze makes the rules. Or so he thinks.

[Chuck 1935]

If you have seperate turn signals you should be good to go. From the picture it looked like one stop light and a back up light. OOOpps!

[WilleyB]

Quote:

Originally Posted by Bruce and Jenna The existing stop light has separate wires for Stop and Turn, as well as Ground. The new one has wires labeled the same. So I assumed that I could connect the Stop wire from the new light to the Stop wire from the old light. No? Don't piss him off. He who holds the booze makes the rules. Or so he thinks.

Just a thought from the peanut gallery, are you sure one of those wires is not for a park light.

Cheers
Willey

[Workshop]

The existing stop light has separate wires for Stop and Turn, as well as Ground. The new one has wires labeled the same. So I assumed that I could connect the Stop wire from the new light to the Stop wire from the old light. No?

ans....Yes...on the new light connect Stop to Stop. As you will not be using the Turn function, I would test the light to see which bulb/LEDs light up. If they all light on the Stop...just connect the Stop wire, if some/half work for Stop and the other for the Turn...use both wires so all the bulbs/LEDs light on the new fixture.

Could I attach long wires to the new light, maybe wrapped around large nuts for weight? Then push my fish tape horizontally toward the wire to snag 'em? Rather than trying to find the hole?

ans...That should work. For the distance you are going....a straightened out coat hanger should work if you don't have a tape.


Yeah, if I find studs, I could run the wire straight down. I could connect to a set of wires under the corner of the bumper for a trailer connection. Heck, I might just choose this anyway, if I can't easily catch my fish.

ans...Even though our rear caps are different...Mine was passable...believe the walls studs were in place before the cap was installed, unlike the side walls construction. Would guess you might be able to get to the new hole without being in a wall section. Just try to keep the end of the tape 'running' along the inside of the glass. Put a slight 'bow' on the tape and that will help keep it near the glass as you feed it toward the hole or string/nut.

[meworrynot]

I was changing the rear marker lights on my MH and the wires for the left outer light dropped into the cavity, shoulda' put vise grips or something to hold them dang it. I was able to retrieve them from the next light in line (in the center) and used mechanics wire to fish them back through. It took some patience.... and cussing, but it worked. Once I could see the wire I used another short piece to grab it as the holes are 1" and fingers too big.

Good luck!

[rockintom]

OK Bruce, I didn't read your post as instructed. But after your last little electrical fiasco....I thought you'd learned your lesson!!! Don't worry, I won't share your little secret. Your secrets good with me....unless I get a dawg-gone good bribe...like a case of Oak Poop!!! Your buddy....rockin'

[Still Working "NOT"]

Quote:

Originally Posted by rockintom OK Bruce, I didn't read your post as instructed. But after your last little electrical fiasco....I thought you'd learned your lesson!!! Don't worry, I won't share your little secret. Your secrets good with me....unless I get a dawg-gone good bribe...like a case of Oak Poop!!! Your buddy....rockin'

It's in the mail!!

[rockintom]

OK Still........you're starting something here. For 3 cases....I'll disclose it here in front of God and everybody. I can be bought!!! Can I get a witness??? OK then, do I hear 3 cases??? I'm so bad!! Then I hafta think.....would my little GD be proud of me???....she don't need to know nothing.....OK I'm still back up to 3 cases!!

[MonacoMama]

Sheesh Tom...why don't you take this silliness to the "Off-Topic Thread" and not degrade poor Bruce's thread anymore than you have?

[rockintom]

Quote:

Originally Posted by MonacoMama Sheesh Tom...why don't you take this silliness to the "Off-Topic Thread" and not degrade poor Bruce's thread anymore than you have?

Darn Mama.....you're a bit fiesty for being gone so long.....