Quote: ''How do I tell if the coil is bad or the points are bad?''The only way I know of to tell if a coil is bad is to replace it. Do try stretching the pigtail a bit and see if that helps; but other than that, it's hard to find most coil problems with a test light or voltmeter. You can do voltage and resistance readings on the coil, but except for continuity (showing a complete open or a dead short), these won't tell you much. This is because they are static readings (ignition system not operating); and the coil usually fails due to breakdown of the insulation between windings, which occurs only when there is high voltage across the secondary of the coil, which occurs only when the ignition system is operating (dynamic). Ah, but the points. The points... Look at your dashboard ammeter with the ignition on but without cranking the motor. You should show an approximate three-amp discharge. No discharge? The points are not closing or not making good contact, or there is an open elsewhere in the system. Normal discharge? Crank the engine. You should see the ammeter fluctuate as the points open and close. No fluctuation? The points are likely shorted, not opening for some reason, or there is a short elsewhere in the system. Ammeter behaving normally? Now is the time to consider trying another coil.
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