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Old 28-02-21, 02:36 PM
dwomby dwomby is offline
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Join Date: Oct 2014
Location: Florida / Nova Scotia
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Quote:
Originally Posted by John Simmons View Post
I can't answer all of your questions, but I can tell you what the ballast relay is/was for in older cars that I am familiar with. In older cars with an ignition coil and a distributor with points it is necessary to have 12 volts to the coil for starting and 9 volts to the coil for running. There are therefore 2 circuits to the coil from the battery, one of which incorporates a resistor (the ballast resistor) to reduce the voltage to 9 volts. The ballast relay switches between these 2 circuits. The relay is sometimes incorporated into the starter motor solenoid circuits when these are part of the starter.
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Quote:
Originally Posted by John Simmons View Post
Oh, I looked at your picture last after posting. Right below and in parallel with the terminal strips is a tan ceramic looking block which appears to be a ballast resistor (it looks similar to ones I am familiar with).
John, thank you for the very helpful replies. I never knew about older cars using different voltages across the coil but that makes sense. Much appreciated.

David
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