All my trailer lights work except for the right side brake light. The right side turn signal works but no brake light. They are LED lights
Yellow is the wire for left brake light and green is the wire for right brake light, where do the two wires tie in together ? I am thinking that somewhere the green has to tie into the yellow, right ?

I would appreciate any help

Since the same wire and lighting is used for both brake and turn signals, first thing I'd do is get a test light or meter and validate that you're getting juice out of that wire on the truck harness when the brakes are applied. A lot depends on the vehicle, but if you're not getting juice/signal to the trailer it could be a fuse, flasher assy, etc?? From the trailer's perspective, if your turn signal works the brake lights should also work.

Since the same wire and lighting is used for both brake and turn signals, first thing I'd do is get a test light or meter and validate that you're getting juice out of that wire on the truck harness when the brakes are applied. A lot depends on the vehicle, but if you're not getting juice/signal to the trailer it could be a fuse, flasher assy, etc?? From the trailer's perspective, if your turn signal works the brake lights should also work.

a friend just stopped over and we tried his truck and all my trailer lights work, so the problem is with my truck socket. there is no juice or current to the right stop light pin. The trailer wiring is fine. How do I determine what is causing no current to the right brake light pin ? Brake light fuse is good and the flasher assembly is fine and working for both turn signals. Still no right side brake light

Thank you for all the help

Rebs,
Grab your owners amnual, and look for a 2nd (or 3rd) fuse block. Sounds like you may have a set of fuses dedicated to the trailer plug. What vehicle are we talking about, someone here should know where else to look.
HRG

always check fuses first

keep it simple!!!

PJ and others are right. First check for specific fuses for trailer brake lights (I hesitate to think it's this because your other brake light works as does the turn lamp on the "bad" side, but it's easy enough to check). After that you'll need to start checking the wiring harness. If your wiring includes one of those "T" assemblies that basically splice into the truck wiring I'd start there to insure clean solid connections.

Unless it's a fuse no easy answer on this one because your turn signal on the same side works, which takes much of the wiring out of the picture. I actually had an issue like this and ended up having to have the "power box" (box under hood with all of the fuses in it) replaced because an integrated relay for the trailer lights had gone bad. That took a good wiring diagram and meter and some time to trace back.

Basically (after fuse checks) start at the plug where you don't have juice now and work forward until you find juice or a problem.

Certainly, fuses are on my list of things to check, but they aren't first. My personal experience is that I have trouble with trailer harness plugs/sockets (usually the ones on the truck) corroding more often than fuses blowing- so far it's 4 corroded connectors vs. 1 fuse. Regarding the original question here, that does sound more like a fuse.

vehicle is a 2003 yukon with factory installed 7 connector socket, six blades and a center pin. it looks like the socket is all one piece, I cannot figure out how to unplug the wires from the socket.
I found trailer light fuses and they are fine.

vehicle is a 2003 yukon with factory installed 7 connector socket, six blades and a center pin. it looks like the socket is all one piece, I cannot figure out how to unplug the wires from the socket.
I found trailer light fuses and they are fine.

That same factory connector socket on my 2004 Suburban had some corroded connectors. I found that installing and removing the trailer plug several times eventually cleaned the contacts enough to make them work reliably.

I wouldn't mess with the wires to the socket. IIRC- There should be an electronic module on your Yukon that connects to the vehicle brake and turn signal wires (which activate different light bulb filaments on your Yukon, I believe) and combines those wires to activate the common brake/turn signal filaments in your trailer bulbs. That's where you may want to look for a loose wire or other problem.

vehicle is a 2003 yukon with factory installed 7 connector socket, six blades and a center pin. it looks like the socket is all one piece, I cannot figure out how to unplug the wires from the socket.
I found trailer light fuses and they are fine.
You didn't say if you checked the wire in back of the socket for 12volts with the brakes applied-let us now if it has power,i no you said the socket doesnt.If it does have power clean the terminals with a small file-if it doesnt let us no ill look up the wire diagram at work,and tell you were the prob is.

You didn't say if you checked the wire in back of the socket for 12volts with the brakes applied-let us now if it has power,i no you said the socket doesnt.If it does have power clean the terminals with a small file-if it doesnt let us no ill look up the wire diagram at work,and tell you were the prob is.

no the wire right behind the socket does not have power when the brake pedal is pushed, but it does have power when the turn signal is on.

no the wire right behind the socket does not have power when the brake pedal is pushed, but it does have power when the turn signal is on.
Ok ill check the wiring diagram,so you have a factory trailer pkg with no electric brake controller under dash right.Are you confident in tracing a broken or corroded wire.Obviously your right brake light on the yukon works correct.It sounds like you have 2 choices in a rush just run a wire from your right rear brake light on the yukon down to the wire with no power-or your going to have to trace the wire up from the socket to find were it gets its power-somwere from the rear to the fuse block right under the dash to the left.I will look into the wiring diagram and see if their is a break from the fuse block to the rear socket for ya.

Ok ill check the wiring diagram,so you have a factory trailer pkg with no electric brake controller under dash right.Are you confident in tracing a broken or corroded wire.Obviously your right brake light on the yukon works correct.It sounds like you have 2 choices in a rush just run a wire from your right rear brake light on the yukon down to the wire with no power-or your going to have to trace the wire up from the socket to find were it gets its power-somwere from the rear to the fuse block right under the dash to the left.I will look into the wiring diagram and see if their is a break from the fuse block to the rear socket for ya.

Thank you very much I appreciate it

that is correct I have no brake control under the dash and it is a factory installed trailer hitch with plug

The problem was a module up under the drivers side dashboard. It conbines the turn signal and stop light for the trailer because the trailer only has one light and the truck has a red stop light and an amber turn signal.
This module was $66.00.

Thank you to all who responded and keep this module in mind if anyone else has the same problem.

The problem was a module up under the drivers side dashboard. It conbines the turn signal and stop light for the trailer because the trailer only has one light and the truck has a red stop light and an amber turn signal.
This module was $66.00.

Thank you to all who responded and keep this module in mind if anyone else has the same problem.Great to hear was just about to send you the wire diagram from the module to the back.

my turn and stop lights on the right side of my trailer don't work. the left side works fine. the running lights works for that side. i check the fuses none blown.

my turn and stop lights on the right side of my trailer don't work. the left side works fine. the running lights works for that side. i check the fuses none blown.
The stop and turn signal is the same bulb, have you replaced it yet?
HRG