I apply brake pedal the trailer lights turn off. the right turn signal lights up both left and right

when you said neither works are you saying they do not light up at all? is it both sides or just one if you tell us this we can and will help you. Thanks Mike L.

test your brake light switch

Stop Lamps
The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides a 5-volt reference voltage and low reference to the brake pedal position sensor. The position sensor provides an analog voltage signal back to the BCM that will increase as the brake pedal is applied. When the brake is applied, the BCM will then apply battery voltage to the left and right stop/turn signal lamp supply voltage circuits and the center high mounted stop lamp (CHMSL) supply voltage circuit illuminating the stop lamps. At the same time the BCM applies battery voltage through the signal circuit to the transmission control module (TCM) and the engine control module (ECM) indicating that the brakes are applied.
Ground for the stop lamps is supplied as follows:
• G402 provides ground for the left rear stop/tail/turn signal lamps
• G403 provides ground for the right rear stop/tail/turn signal lamps
• G301 provides ground for the CHMSL
The stop lamps on this vehicle will not illuminate unless the ignition is in the accessory, run, or crank positions. When the ignition is in the OFF position the stop lamps will not illuminate when the brake pedal is applied.
Battery voltage from the LT TRN/SIG and RT TRN/SIG fuses located in the rear fuse block is also used by the body control module (BCM) for stop lamp operation.

Turn Signal Lamps
Battery voltage supplied to the body control module (BCM) from the fuses listed below is used for turn signal and hazard lamp operation.
• LT TRN/SIG fuse for the left turn signals
• CTSY/RF TRN fuse for the right front turn signal
• RR TRN/SIG fuse for the right rear turn signal
When the turn signal switch is place in either the LEFT or RIGHT position, ground from G300 is applied through the turn signal switch signal circuit to the BCM indicating the turn signal request. In response to this signal, the BCM applies a pulsating voltage to the front and rear turn signal lamps supply voltage circuits cycling the lamps ON and OFF. At the same time the BCM sends a GMLAN serial data message to the instrument panel cluster (IPC) to cycle the appropriate turn signal indicator ON and OFF.
Ground for the turn signal lamps is supplied as follows:
• G104 provides ground for the left and right front turn signal lamps
• G402 provides ground for the left rear stop/tail/turn signal lamps
• G403 provides ground for the right rear stop/tail/turn signal lamps

Do you have a factory scan tool (tech2) ? Your best bet , take it to the dealer .

There are three fuses involved.
There is a 25 amp fuse before the brake switch located in the fuse box under the hood. Then there are two 15amp fuses after the brake switch in the box inside the cabin. One is for the lower brake lights and the other is for the high mount light and the trailer connector.
You would need to know if the 15amp fuse for the lower lights has power when the brake pedal switch is applied.

make left turns only?

Check the trailer wires for damaged wires that may be crossing.

Turn Signal Lamps
The LT T/SIG and RT T/SIG fuses located in the underhood fuse block supplies battery positive voltage to the body control module (BCM) for turn signal and hazard lamp operation. When the turn signal switch is place in either the LEFT or RIGHT position, ground from G202 is applied through the turn signal switch signal circuit to the BCM indicating the turn signal request. In response to this signal, the BCM applies a pulsating voltage to the front and rear turn signal lamps supply voltage circuits cycling the lamps ON and OFF. The BCM also sends a message via GMLAN to the instrument panel cluster (IPC) to cycle the turn signal indicator ON and OFF depending on the position of the turn signal switch.
Ground for the turn signal lamps is supplied as follows:
• G101 provides ground for the left front turn signal lamp
• G100 provides ground for the right front turn signal lamp
• G302 provides ground for the left and right rear turn signal lamps

The LT T/SIG and RT T/SIG fuses located in the underhood fuse block are also used by the body control module (BCM) for stop lamp operation.
The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides both, a 5-volt reference voltage and low reference to the brake pedal position sensor. The position sensor provides an analog voltage signal back to the BCM that will increase as the brake pedal is applied. When the brake pedal is applied, the BCM will then apply battery voltage to the left and right stop lamp supply voltage circuits and the center high mounted stop lamp (CHMSL) supply voltage circuit illuminating the stop lamps. At the same time the BCM signals the transmission control module (TCM) and the engine control module (ECM) that the brakes are applied. Ground for all stop lamps is provided at G302.
The stop lamps on this vehicle will not illuminate unless the ignition is in the accessory, run, or crank positions. When the ignition is in the OFF position the stop lamps will not illuminate when the brake pedal is applied.

Did you check the fuse's. ? Wouldn't think it's a ground because right an left tail lamp Assembly's use same ground ! Did you check for B+ voltage at the bulb. with a volt meter ? Power is supplied by the BCM . Could be the tail lamp assembly

If the brake and turn signal are on the same bulb than you can Orin straight wiring. If the brake and turn signal are on different bulbs than you'll need a wiring harness with a converter box. I'm pretty sure the wrangler has the brake and turn signal on the Same bulb so let's start with basic trailer wiring. The green wire on the trailer harness is for the right side turn and brake for the trailer. This wire should be attached to the wire on the vehicle that supplies power to the right turn signal/ brake light. The yellow wire is the left turn signal, brake light on the trailer and should be attached to the wire on the vehicle that supplies power to the left turn signal /brake light. The brown wire is the tail lights on the trailer and should be attached to either the left or right side wire on the vehicle that supplies power to the tail lights. The white wire is grounD and it is vitally important that this wire be attached to the vehicle in a manor that supplies a good ground. Failure to suppy a good ground will result in all kinds of funky problems with the trailerer lighting such as all the lights linking when the tail lights and turn signals are on at the same time. If you have any specific questions I will be more than happy to try and help. Good luck.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

One wire is for the brake/directional filament and the other wire is for the tail light. The fixture should be grounded when it is attached to the bracket. To test which is which (the brown wire is USUALLY the ail light) make sure the fixture is grounded and touch a hot wire to each of the wires coming from the fixture. Watch to see which wire lights up the brighter filament and this is the brake/directional light. The dimmer filament if the tail light. Brakes lights and directional lights are both the same filament. Wen the brakes are applied, both lights are activated. When a direction light is turned on, it simply flashes the brake light filament.

I found the problem. Talking with a technician from the controller company, we determined that it was a fuse problem. I found that the fuse to the CHMSL was blown.