A rotor arm sits inside the distributor cap and transfers the charge from the ignition coil to the multiple touchpoints for the engine cylinders. Enter your registration number to find the right one for your vehicle.
The ignition system is made up of many components, all of which play an important role in getting the engine started. As the charge is carried from the ignition module through the coil and into the cap, the rotor arm spins, allowing it to connect with the multiple touchpoints or posts that are connected to the spark plugs in the engine.
The rotor arm doesn't actually touch these posts - the charge jumps across a small gap to reach them - so the ignition system fails if it becomes dislodged or stops spinning. The rotor arm can also overheat, burn and become difficult to remove under the distributor cap, so be sure to consult a mechanic if this is the case.