However, a component with a high current consumption must not be connected using wires which are too thin, or the wires will overheat, blow a fuse, or burn out.
The two components are connected in series so that the varying resistance in the sender will affect the position of the needle on the gauge.
The current would encounter the resistance twice, and the double resistance would halve the current, so that the bulbs would glow only feebly. Connecting the bulbs in parallel means that electricity goes through each bulb only once.
Modern cars often need room for many wires in confined spaces. Some manufacturers now use printed circuits instead of bundles of wires, particularly at the rear of the instrument panel.