how to test ignition coil resistance
To perform a standard ignition coil primary resistance test, the ignition should be off in the car. Once the two low voltage coil terminals are disconnected, the resistance should remain between 0.3 and 1 ohms. A switching test uses a 12 VDC test lamp. A small straight pin should be inserted into the wire that runs the negative coil to the TFI module. The pin can then be connected to the lamp.
Ignition coil resistance tests are used on the secondary aspects of the ignition coil. These tests should be performed with caution because the circuits of the secondary part of the ignition can have very high voltage. These tests should only be performed if there was inconclusive evidence in any of the primary tests.