98 forester Brake light schematic

pull your brake light assmb out and check your connections including ground

Have you checked for 12 volts going to the brake light switch and have you pulled the complete brake/tail light assemblys out to ck for melted curcuit boards on the back side where the bulbs go in ? I not ... start with the Tail light cutcuit boards they melt all the time .

first remove the wire you hook up rear tail and break circuit. (1)install ground wire to the frame (2)turn on the head light switch and go to the rear to find the +12 volt on the wire then hook it up to the led tail circuit, it should only light up that circuit but if both still come on then the new led unit is not config right. Replace it or have it modified. if only the tail circuit is on then go to (3)cut off the head light switch and have someone step on the break peddle then fine the +12 volt on the wire and hook it up to the brake led circuit.(only the brake circuit should be on) hope this help you. .

I had a similar issue with my lincoln, it turned out to be the wiring to the socket, was corroded and broken. Since you have done the other things this would be the next plausable place to look. hope this helps

A bad socket is a common enough problem that it is likely that, rather than a wiring problem. Just splice in a new socket, if you can, or whatever is easier and cheaper (like a tail light assembly from a salvage yard).
Of course if you have a voltmeter or testlight, you can check at the socket electrical connector for power when it should be there-when the brake is pressed.

THAT RIGHT IF BRAKE SWITCH BAD NO BRAKE LIGHT WILL WORK.SPRAY ELECTRICAL CLEANER IN BULB SOCKET BULB SOCKET COULD HAVE OXIDATION AND CORROSSION CAUSING POOR CONTACT.

I've got the same problem on 98 GMC Sierra.

I'm an electrical engineer, I checked the electrical diagrams and verified that there is no problem in the rear lamp assembly or wiring. With the light assembly unplugged, I can actually watch the blinker and brake signals operate with a voltmeter. The Tail light works OK.

It simply won't provide enough current to light the bulbs.

I'm afraid that it's melted one of a pair of normally closed contacts inside the blinker switch that feed the brake and turn separately on each side.

Its a ground...if you have too ...Run a new ground wire to the body....

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

Here is your problem. One of the sockets inside the tail light assy. melted and shorted the circuit. Its like a plate that clicks into the tail light inside the trunk. Remove the plate, by unsnapping it out of the tail light and check the bulbs, by removing them out of the socket. You may find that one bulb melted at bottom and completed the circuit. Nothing more then melted connections. You can buy the whole plate at dealer.