Two wire to three wire tail light converter

[Tom&Shelly]

So, we want to use these tail lights on our teardrop:

but the problem is that the wires come to the trailer from the tow vehicle in the form of a right signal/brake light and left signal/brake light. We, of course, want three wires, one for each of the orange turn signals, and a separate brake light for the red lights. Also, we want to use the center brake light in the picture, which has a brake light wire (as well as a running light wire), but isn't intended for signalling turns. (BTW, I'm an electrical engineer, been building the teardrop for the past year, and have owned the lights since November 2017, yet never noticed we had this problem until yesterday, when I tried to count the number of wires we need to go into the hatch. )

So, I see how one could build a "black box" (CMOS logic and drivers) to deal with this, but, surely, I realized, someone must already make a product that splits the two wires into three; and, in fact, they do:

https://www.etrailer.com/p-118158.html

Great! But, the specs on the device say it is for incandescent bulbs only. Does anyone know why this might be? Seems like some of people in the reviews have used it with LED lights with essentially no problems. So, does anyone have experience with this?

I looked for similar products for LEDs, but so far with no luck. (This device is also sold through Amazon.)

Other solutions, of course, would be to buy a center light that includes turn signals, and either buy a different type of turn signal/back up/brake light set, or a second set like these and replace the orange lights with either a double set of red or white lights. If the 2 to 3 wire tail light converter will work, however, it is the cheaper and more elegant solution.

Thanks in advance for any comments and/or experience.

Tom

 

[Pmullen503]

The specs say to not use on vehicles with led lights, not the trailer. Perhaps vehicles with led lights don't have wiring to handle the current.

 

[troubleScottie]

A typical 4 wire (and 5 and 6 and 7 ) connector has:

ground
right turn/stop
left turn/stop
running light
plus others for the larger connectors.

You want to convert that to
stop
right turn
left turn
and carry through the ground and running lights.

Hopefully the turn signals will have 4 wires: ground, turn, stop and running.


Tekonsha-118158-Taillight-Converter 2 to 3

https://www.amazon.com/Tekonsha-118158- ... &s=gateway


The CURT 56196 2-to-3-Wire Splice-in Trailer Tail Light Converter. I was surprised e-trailer does not carry it. They do carry many curt products.

 

[Tom&Shelly]

Tekonsha-118158-Taillight-Converter 2 to 3

https://www.amazon.com/Tekonsha-118158- ... &s=gateway


The CURT 56196 2-to-3-Wire Splice-in Trailer Tail Light Converter. I was surprised e-trailer does not carry it. They do carry many curt products.

Yep, those are what I want.

The Tekonsha is what E-Trailer sells, but with shipping buying it from them or Amazon is about awash. There are many, many, Amazon customer comments that say it works with LED lights, despite the warning in the description. I decided to buy one to test. Some customers report both turn signal and brake LED lights flash as the brake or turn signals are applied. I can think of a few reasons why and so will experiment and report back.

I didn't see any warnings about not using the Curt device with LED lights. Looks very similar, but I couldn't find a place to buy it either.

Thanks guys!

Tom

 

[H.A.]

Maybe abandon worthless RV level wiring scheme and copy SAE J560 wiring scheme the professionals in trailer towing business standardised on.
Then, either type of tail/turn/brake wiring on the truck, the trailer plugs in and has functional lighting. Every time.
On the other hand, maybe not. Its amusing to see the endless angst of RV guys and their tail light follies.

 

[Tony Latham]

Its amusing to see the endless angst of RV guys and their tail light follies.

Huh?

T

 

[Tom&Shelly]

The two to three wire tail light converter came in the UPS truck this afternoon, and I decided to test it:

I took a scrap of ply and tied the "black box" and the lights together. Used a 4 pin connector, since that's what I had in the junk box. (I assume those particular wires are just jumpered between the 4 pin and 7 pin connector in the Taco.)

We have some Mexican pack rats living on the property, and when they saw the wiring, they admired my nido de ratas magnifico. (Always good to be complimented by professionals!)

Bottom line is it works (on LED lights)

As mentioned by some in the Amazon reviews, the orange lights do flash briefly when the brakes come on. I took many shots, and got one where I captured it

If I had a digital oscilloscope I'd try and figure out what's going on. The orange lights are on so briefly, it doesn't make any practical difference.

When the flashers are on, the red lights flash (and the orange lights also flash briefly).

If the flashers and brake lights are on simultaneously, there is no way to know the brakes are on! This peaked our curiosity: On the Taco itself, the (red) turn signals are also the flashers, and the brakes are separate. However, on our Jeep Wrangler, when the flashers are on, the brakes don't show. Which seems like a safety issue if one is driving slowly with the flashers on.

Incidentally, we first tried this converter and lights on the Jeep, and when pressing the brake, the right orange light came on steady. After some trouble shooting, I realized the 4 pin U haul connector a previous owner installed wasn't making good contact with the high quality Harbor Fright trailer side connector I used. If I squeezed the connectors a little the lights behaved as they should.

Tom

 

[KTM_Guy]

I have the Curt box on my drop for the 3 break light. Works great with my LEDs. If they flash funny it doesn’t bother me because I can’t see it from the drivers seat.

Todd

 

[Tom&Shelly]

I have the Curt box on my drop for the 3 break light. Works great with my LEDs. If they flash funny it doesn’t bother me because I can’t see it from the drivers seat.

Todd

Tom

 

[GTS225-TNT]

OK.....resurrecting this old thread, because I have a convertor build in mind. My teardrop has individual tail, stop, and turn indicators from a 50's vintage firetruck. My Ford F150 has combo turn/stop lamps.

I've built a convertor/adapter to go from the 7-blade round, to the 6-pin round on the tear, but it's heavy and bulky, and I can't imagine it being none to gentle on the socket.
What I'd like to do is attempt to build an adapter, with the 2-to-3-wire convertor contained inside it. The already-built convertors are a bit bulky, and requires a 3" PVC pipe to contain it......that's why my current "fabrication" is so heavy and bulky.

Anybody know where I can get a convertor that hasn't been potted into a black box, or even a schematic and parts list in order to build my own?

Thanks.....Roger

 

[Tom&Shelly]

Hi Roger,

Long time since I've thought about this! My memory is that I saw how a circuit might be designed based on CMOS logic circuits (they are friendly to 12 volts). But I don't think I actually designed one since I found the products were already made. I know I never built or tested a circuit.

The Tekonsha box has mechanical relays inside (we can hear them when up close). It has lived in our galley hatch and hasn't given us any problems. (Works fine with LED's--though it doesn't sound like that is a concern for you.)

I get what you are saying about wanting one that isn't in a potted box, however. Afraid I don't know of any. Perhaps others here do?...

Tom

 

[GTS225-TNT]

(Works fine with LED's--though it doesn't sound like that is a concern for you.)
Tom



Actually, I left that out. Yes, I am using LED's in the fixtures, and the black box I got from Amazon does work with them. I'm just wanting to condense my "proof-of-concept" design and get it lighter so it doesn't tear up my truck mounted socket.