The side and tail lights, however, which you may need to leave on when the car is parked, are always wired independently of the ignition switch. When fitting extra accessories, such as a rear window heater which consumes a heavy current, always wire it through the ignition switch.
Some ancillary components can be operated without the ignition turned on by turning the switch to the auxiliary position. A radio is usually wired through this switch, so that it can be played with the engine off.
The fuses are usually grouped in a box or on a panel with a cover. Ideally, the box should be fixed in an accessible place — such as the bulkhead under the bonnet.
Often, however, it is hidden away, perhaps under the dashboard or down in the front knee-well. The car handbook usually gives the location, but without a book finding the box can prove difficult. Get to know where it is before anything goes wrong.