Unplug the dryer from power.
Unscrew the screws holding the control panel cover in place. Depending on your make and model, the screws may be on the top, back or front of the panel.
Grasp the timer control knob and pull it straight off.
Tilt the control panel cover forward to expose the inner components. Inspect the component that has a plastic rod sticking out of it that the control knob was connected to. It will be off-white color with a connection wire running out of its bottom. The top of the component may be curved.