Faulty wiring or switch: There may be a problem with the electrical wiring or switch that controls the brake lights and indicators. This could cause the brake lights to flash when the indicators are turned on.
Faulty indicator relay: The indicator relay is responsible for controlling the blinking of the indicator lights. If the relay is faulty, it could cause the brake lights to flash instead of the indicators.
Short circuit: There could be a short circuit in the electrical system that is causing the brake lights and indicators to be interconnected.
To determine the exact cause of the issue, I recommend taking the vehicle to an automotive electrician or mechanic for inspection. They will be able to properly diagnose the problem and make the necessary repairs.
