A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a 12 volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it's not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.
In this case you can place a stick between the seat and brake pedal to hold the pedal down. The brake light circuit will be turned on. If the test bulb is only lit up dimly, move the wiring harnesses around in the trunk, wiggle the signal switch, and / or bang around the back of the car with a rubber mallet. If you see the test bulb get bright or flicker, you're in the area of the short.
It sounds like the bulbs in the back are melted here is a guide that can help you fix the problem.
Please let us know what you find.
Wednesday, March 17th, 2021 AT 6:16 PM