Trailer Wiring Questions, Help Please.

[Steve K (IA)]

My sister (HD rider) wants to borrow my Cycle Mate trailer.  18 years ago I wired my bike and trailer with a 5 pin round plug.  She has a 4 pin flat.  I can't find an adapter to convert to save my soul!  I have been told the 5 pin round is kind of odd.  The 5 pin round plugs I'm finding are a much larger diameter so I can't make my own adapter.

So, with my 5 pin plug I have a wire for... 1) brake, 2) L turn, 3) R turn,  4)tail light and 5) ground.  Not only do I pick up ground through the hitch but also through the harness.

I picked up a 2' long 4 pin flat extension thinking I would cut off the connector I don't need and splice it into the trailer harness.  The actual harness on the trailer has 7 wires???

So...  

Here's the Big question.  The wires on the 4 pin extension are marked ground, L turn, R turn, tail light but No brake.  How are the brake lights supposed to be activated?

My trailer has 2 separate brake/tail lights and 2 turn signal lights.  

[MarkT]

The turn signal filiments are also the brake filiments.  Wire the ie. right brake wire to both the right turn signal and the right brake light, in parallel.  Same for the left.

[gordonv]

The turn signal filiments are also the brake filiments.  Wire the ie. right brake wire to both the right turn signal and the right brake light, in parallel.  Same for the left.

So really there is nothing special inside the wiring convertor to bring those 5 wires to a 4 wire plug, maybe only some diodes, so you don't activate the (front) turn signals when you hit the brakes (& vis-a-versa)? (I think this would also be for the turn signal, using one doesn't activate the other).

[WintrSol]

So really there is nothing special inside the wiring convertor to bring those 5 wires to a 4 wire plug, maybe only some diodes, so you don't activate the (front) turn signals when you hit the brakes (& vis-a-versa)? (I think this would also be for the turn signal, using one doesn't activate the other).

Yes, assuming the HD has separate brake and rear signals, it has a circuit that combines them, 3 into 2. If so, you just need to connect the L and R from the 4-pin connector to the L and R in your 5-pin. If the trailer has amber lenses on the signals, you will need to make them red, somehow. Red LED bulbs, a sheet of red plastic film, something.

[Steve K (IA)]

So really there is nothing special inside the wiring convertor to bring those 5 wires to a 4 wire plug, maybe only some diodes, so you don't activate the (front) turn signals when you hit the brakes (& vis-a-versa)? (I think this would also be for the turn signal, using one doesn't activate the other).

Yes, assuming the HD has separate brake and rear signals, it has a circuit that combines them, 3 into 2. If so, you just need to connect the L and R from the 4-pin connector to the L and R in your 5-pin. If the trailer has amber lenses on the signals, you will need to make them red, somehow. Red LED bulbs, a sheet of red plastic film, something.

Okay, so here is what my trailer looks like.  Amber turns on top of the red running, brake lights.
https://www.cyclematetrailers.com/page/page/2854518.htm

I'm not replacing my 5 pin plug.  Hoping to splice a 4 pin flat connector further back in the trailers harness.  So when they are done with it, I can coil it up and zip tie it up out of the way and hope they never ask to borrow it again.  I just have a bad feeling.... 

[da prez]

The trailer has European wiring. Have her get a converter and wire her bike to your trailer. You have a converter on your bike to use that plug.  The other option is magnetic lights and standard for her bike.

              da prez

[Steve K (IA)]

The trailer has European wiring. Have her get a converter and wire her bike to your trailer. You have a converter on your bike to use that plug.  The other option is magnetic lights and standard for her bike.

              da prez

I don't know about European wiring on the trailer.  Like I said I seen a small square plug under the trailer with 7 wires going in and out, about 3/4" square.  I don't have any converter on my bike...none that I added.  I wired it following instructions by Wayne Herbert who has had a write up in shop talk.  I accessed and tapped (hardwired) into the wires I needed under the seat along the right side of the rear fender. 
I'm thinking of bugging out those wires under the trailer at that plug and just go with the red running/brake lights and for this Harley thing forget about the amber turn signal lights and just use the red lights for turns.  Does this sound right?   
The way I see it in my head if I try and wire in the actual turn lights, say the HD turns on the left turn signal, the left amber and both reds will blink...vice versa for a right turn.  Hitting the brakes, all 4 lights will light up.

[WintrSol]

OK, the HD has four wires, and two are left signal+brake, right signal+brake. That means when the brake is applied, both are on, and when a signal is applied, that side cycles on and off; if the brake is applied while the signal is on, one flashes on and off, the other is just on.

Your trailer came with a 5-pin connector, so the two red lamps have two brightness levels or two bulbs each, running and brake, and the running lights are wired together, as are the brake lightsl. So, if you connect the HD's L+B wire to both the trailer L and B wires, and the HD's R+B wire to the trailer R and B wires, you will have connected all four lamps together. That means applying the brake lights all four, and just one signal will flash all four; brake and signal means all four will be on, like brake only. I think the 7 wires into the combiner is just the four tail lamps, ground, running left, and running right (there are other possibilities). If you can swap the red lenses with the amber lenses, I would do that, and just connect the HD's L/B to the trailer's L, and R/B to the trailers R.

[Steve K (IA)]

OK, the HD has four wires, and two are left signal+brake, right signal+brake. That means when the brake is applied, both are on, and when a signal is applied, that side cycles on and off; if the brake is applied while the signal is on, one flashes on and off, the other is just on.

Your trailer came with a 5-pin connector, so the two red lamps have two brightness levels or two bulbs each, running and brake, and the running lights are wired together, as are the brake lightsl. So, if you connect the HD's L+B wire to both the trailer L and B wires, and the HD's R+B wire to the trailer R and B wires, you will have connected all four lamps together. That means applying the brake lights all four, and just one signal will flash all four; brake and signal means all four will be on, like brake only. I think the 7 wires into the combiner is just the four tail lamps, ground, running left, and running right (there are other possibilities). If you can swap the red lenses with the amber lenses, I would do that, and just connect the HD's L/B to the trailer's L, and R/B to the trailers R.

Thanks.
Actually the red lights have 2 filament (1157) bulbs, one each side.  The amber ones have 1156 1 filament bulbs.   

[WintrSol]

OK, the HD has four wires, and two are left signal+brake, right signal+brake. That means when the brake is applied, both are on, and when a signal is applied, that side cycles on and off; if the brake is applied while the signal is on, one flashes on and off, the other is just on.

Your trailer came with a 5-pin connector, so the two red lamps have two brightness levels or two bulbs each, running and brake, and the running lights are wired together, as are the brake lightsl. So, if you connect the HD's L+B wire to both the trailer L and B wires, and the HD's R+B wire to the trailer R and B wires, you will have connected all four lamps together. That means applying the brake lights all four, and just one signal will flash all four; brake and signal means all four will be on, like brake only. I think the 7 wires into the combiner is just the four tail lamps, ground, running left, and running right (there are other possibilities). If you can swap the red lenses with the amber lenses, I would do that, and just connect the HD's L/B to the trailer's L, and R/B to the trailers R.

Thanks.
Actually the red lights have 2 filament (1157) bulbs, one each side.  The amber ones have 1156 1 filament bulbs.   

Umm, yeah, forgot about the running lights. If you want both brake and signal operation, you will need to somehow change the color of the amber lenses to red. A red plastic film to line the inside of the lenses would be the least difficult; that, or replace the white or amber 1156 bulbs with red LEDs. The only way to use the brake lights as signals is to do surgery on the trailer wiring to separate the two brake lamps and connect them to the L+B an R+B wires from the HD.

[da prez]

  American wiring is standard. Yellow is left , green is right , brown is tail , white is ground. The brake light /stop is controlled thru the turn indicator switch. European uses separate wires for the brake/turn lights. I do not have a wiring diagram in front of me and I have not had coffee as of yet. 
  The European wiring is similar to that used on a semi truck/trailer.

                                     da prez

[WintrSol]

  American wiring is standard. Yellow is left , green is right , brown is tail , white is ground. The brake light /stop is controlled thru the turn indicator switch. European uses separate wires for the brake/turn lights. I do not have a wiring diagram in front of me and I have not had coffee as of yet. 
  The European wiring is similar to that used on a semi truck/trailer.

                                     da prez

While it is useful knowing that, the problem is converting the 4-wire standard to the 5-wire standard. There is no direct or simple way, so the OP has to get creative. Without modifying the trailer wiring, the only way, IMO, is to change the color of the amber signals on the trailer to red, and use them as turn+stop per the 4-wire standard.

[Steve K (IA)]

Well, just finished up splicing the 4 pin plug into my trailer. 

Plug - yellow to yellow & jumper to red - on trailer
       green to  green & jumper to red
       brown to brown
       white to white

As suggested..... the way I understood it, I ran jumpers from both turns to the red brake wire on trailer.
 Plugged the original 5 pin round into my bike to see what would happen.  OH BOY! 
No matter what I do with my bike...turns or brake, ALL lights, brake and turns come on on the bike and trailer.  Use a turn signal, All lights on bike and trailer flash. All lights.

I wonder how this is going to work when plugged into the brother in laws HD

I have to pull this thing 80 miles to my sisters house early tomorrow.  The way it is, I won't be able to plug the lights in.  Hope I don't get stopped.

Can anyone see what I did wrong or will it react different when the 4 pin plugs into the HD? 

[WintrSol]

The same thing will happen - all the lights are connected together, so when one on the bike is on, all on the trailer will be on. You can't use the brake lights on the trailer, only the signal lights.

[Steve K (IA)]

The same thing will happen - all the lights are connected together, so when one on the bike is on, all on the trailer will be on. You can't use the brake lights on the trailer, only the signal lights.

Okay,  do I cut the jumpers to the red brake wire and then he will have turns and tail?
Also would my 5 pin plug work again if I cut the jumpers?

The HD is a dresser and the turn signals are on the trunk, the brake light down on the fender where it won't be seen.  He may just have to ride in the middle of his group.  6 couples are going to TN.  Don't know how many bikes.  My sister and BiL each have a bike.  

[WintrSol]

The same thing will happen - all the lights are connected together, so when one on the bike is on, all on the trailer will be on. You can't use the brake lights on the trailer, only the signal lights.

Okay,  do I cut the jumpers to the red brake wire and then he will have turns and tail?
Also would my 5 pin plug work again if I cut the jumpers?

The HD is a dresser and the turn signals are on the trunk, the brake light down on the fender where it won't be seen.  He may just have to ride in the middle of his group.  6 couples are going to TN.  Don't know how many bikes.  My sister and BiL each have a bike.  

Yes, you will have turn signals and tail lights, and, when he applies the brakes, both turn signals will light, because the signals and brakes are combined in the HD wiring. This is why I suggest changing the color to red.

[Steve K (IA)]

The same thing will happen - all the lights are connected together, so when one on the bike is on, all on the trailer will be on. You can't use the brake lights on the trailer, only the signal lights.

Okay,  do I cut the jumpers to the red brake wire and then he will have turns and tail?
Also would my 5 pin plug work again if I cut the jumpers?

The HD is a dresser and the turn signals are on the trunk, the brake light down on the fender where it won't be seen.  He may just have to ride in the middle of his group.  6 couples are going to TN.  Don't know how many bikes.  My sister and BiL each have a bike.  

Yes, you will have turn signals and tail lights, and, when he applies the brakes, both turn signals will light, because the signals and brakes are combined in the HD wiring. This is why I suggest changing the color to red.

Okay, thanks.  I picked up some 3M transparent tape to temporally line the amber lens.  I'll cut the jumpers and hope my 5 pin connector will work for the ride over to their place. 
Again, Thanks a Bunch. 

[da prez]

  You asked . The thing you did wrong is modify the trailer to loan it out. IMO , they should have changed the HD.  Also , ask them to wash the oil off the trailer before returning it.

                                        da prez

[Steve K (IA)]

  You asked . The thing you did wrong is modify the trailer to loan it out. IMO , they should have changed the HD.  Also , ask them to wash the oil off the trailer before returning it.

                                        da prez

I TOLD the BIL twice it had a 5 pin plug.  He went ahead and let them put on a 4 pin.  He's an idiot!  He doesn't even know how to take his seat off.    I got it so the lights are somewhat passable.  I just have a really bad feeling about this.  Not worried so much about oil, it will wash off.  I just may end up with a new trailer because I don't think it will come back the same way it left. 

[gordonv]

I just may end up with a new trailer because I don't think it will come back the same way it left. 

Can you say "upgrade"?