Where is the diesel pre heater relay fitted on a 406 hdi?

On a Peugeot 406 HDi, the diesel pre-heater relay is typically located in the engine bay fuse box. It can be identified by its labeling or by consulting the vehicle's manual for specific diagrams. If you have difficulty locating it, checking under the dashboard or near the battery might also help, as some models may vary slightly in relay placement.