The best way would be to connect a test light lead to bttery positive and the light to the ground side of the coil (lead going to points) if the lead gets shorted the test light will illuminate and stay on as long as the short to ground is present.
You can use a regualer 12 volt bulb 1156 whatever , just solder a few leads to it and connect to system at the respective test points as described. Voila just drive till it quits...status of the light will indicate if that is the issue or not. LA Tech
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