How do I tell if I have a ballasted coil?

If the coil housing is not identified as ‘standard’ or ‘ballasted’ it can be checked with a multimeter set to Ω. 

Use the instrument to test between the (+) and (–) terminals and check the reading. A standard system coil should read around 3 Ω, while a ballasted system unit should register at 1.5 Ω.