How Turn Signals Work

By: Karim Nice

The Wiring

Let's take a look at how the turn-signal circuit is hooked up.

The turn-signal circuit gets power when the ignition key is on. The power goes through a fuse panel into the thermal flasher. From there it goes to the stalk on the steering column.


Depending on the position of the turn-signal stalk, the power either stops in the switch or gets sent to the left or right turn-signal lights (including the indicator lights on the dashboard). Power flows through the filament of the lights and then is grounded.

This is all fairly straightforward, but you might be a little surprised at how the thermal flasher works.