[12Ounce]

Sometimes these problems can only be found with voltmeter ... and the measurements must be made during high current draw, i.e., during cranking. This can make some measurements very difficult.

I once found the ground lead on the engine block, connected to a stud used for starter attachment, would rise more than 1/2 volt positive during cranking. It turned out that an anti-sieze material that used on the stud was acting as a partial insulator. The stud was removed and cleaned and a "whole heap" of electrical problems disappeared.