What causes the warning lights to come on when you use the indicators either way on a Peugeot 405 estate on a K reg?

The warning lights on a Peugeot 405 estate may activate when using the indicators due to a faulty flasher relay or a short circuit in the indicator wiring. Additionally, a blown fuse or malfunctioning bulbs can cause the system to send a warning signal. It's also possible that a poor ground connection is leading to electrical feedback, triggering the warning lights. Checking the indicator circuit and related components can help identify the specific issue.