Vintage Vehicle Grounding Polarity & Voltage Look Up Tool

Sonic Heritage · Bench Reference

Vintage Vehicle Grounding & Voltage Reference

Expand your vehicle make, then find its model year to read the chart's ground polarity and estimated system voltage.

Classic US automobiles, 1932 through 1957. The source chart omits 1943 through 1945. Use the arrow beside each make to open or close its table.

AUBURN

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

BUICK

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Negative ground	6V (estimated)
1938	Negative ground	6V (estimated)
1939	Negative ground	6V (estimated)
1940	Negative ground	6V (estimated)
1941	Negative ground	6V (estimated)
1942	Negative ground	6V (estimated)
1946	Negative ground	6V (estimated)
1947	Negative ground	6V (estimated)
1948	Negative ground	6V (estimated)
1949	Negative ground	6V (estimated)
1950	Negative ground	6V (estimated)
1951	Negative ground	6V (estimated)
1952	Negative ground	6V (estimated)
1953	Negative ground	6V (estimated)
1954	Negative ground	6V (estimated)
1955	Negative ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

CADILLAC/LASALLE

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Negative ground	6V (estimated)
1947	Negative ground	6V (estimated)
1948	Negative ground	6V (estimated)
1949	Negative ground	6V (estimated)
1950	Negative ground	6V (estimated)
1951	Negative ground	6V (estimated)
1952	Negative ground	6V (estimated)
1953	Negative ground	6V (estimated)
1954	Negative ground	6V (estimated)
1955	Negative ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

CHEVROLET

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Negative ground	6V (estimated)
1938	Negative ground	6V (estimated)
1939	Negative ground	6V (estimated)
1940	Negative ground	6V (estimated)
1941	Negative ground	6V (estimated)
1942	Negative ground	6V (estimated)
1946	Negative ground	6V (estimated)
1947	Negative ground	6V (estimated)
1948	Negative ground	6V (estimated)
1949	Negative ground	6V (estimated)
1950	Negative ground	6V (estimated)
1951	Negative ground	6V (estimated)
1952	Negative ground	6V (estimated)
1953	Negative ground	6V (estimated)
1954	Negative ground	6V (estimated)
1955	Negative ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

CHRYSLER

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

CORD

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

CROSLEY

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

DESOTO

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

DODGE

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

DUESENBERG

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Negative ground	6V (estimated)
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

ESSEX

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

FORD

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

FRANKLIN

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

FRAZER

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

GMC TRUCKS

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Negative ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

GRAHAM

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

HUDSON

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

HUPMOBILE

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Not listed	Not determined
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

KAISER

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Not listed	Not determined
1957	Not listed	Not determined

LINCOLN

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Negative ground	6V (estimated)
1938	Negative ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

LINCOLN-ZEPHYR

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

MARMON

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

MERCURY

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

METROPOLITAN

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Positive ground	6V (estimated)
1957	Positive ground	6V (estimated)

NASH/LAFAYETTE

Year	Ground polarity	Estimated voltage
1932	Varies; verify vehicle	Not determined
1933	Varies; verify vehicle	Not determined
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

OLDSMOBILE

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Negative ground	6V (estimated)
1938	Negative ground	6V (estimated)
1939	Negative ground	6V (estimated)
1940	Negative ground	6V (estimated)
1941	Negative ground	6V (estimated)
1942	Negative ground	6V (estimated)
1946	Negative ground	6V (estimated)
1947	Negative ground	6V (estimated)
1948	Negative ground	6V (estimated)
1949	Negative ground	6V (estimated)
1950	Negative ground	6V (estimated)
1951	Negative ground	6V (estimated)
1952	Negative ground	6V (estimated)
1953	Negative ground	6V (estimated)
1954	Negative ground	6V (estimated)
1955	Negative ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

PACKARD

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

PIERCE-ARROW

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

PLYMOUTH

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

PONTIAC

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Negative ground	6V (estimated)
1938	Negative ground	6V (estimated)
1939	Negative ground	6V (estimated)
1940	Negative ground	6V (estimated)
1941	Negative ground	6V (estimated)
1942	Negative ground	6V (estimated)
1946	Negative ground	6V (estimated)
1947	Negative ground	6V (estimated)
1948	Negative ground	6V (estimated)
1949	Negative ground	6V (estimated)
1950	Negative ground	6V (estimated)
1951	Negative ground	6V (estimated)
1952	Negative ground	6V (estimated)
1953	Negative ground	6V (estimated)
1954	Negative ground	6V (estimated)
1955	Negative ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

REO

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

STUDEBAKER

Year	Ground polarity	Estimated voltage
1932	Positive ground	6V (estimated)
1933	Positive ground	6V (estimated)
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Positive ground	6V (estimated)
1940	Positive ground	6V (estimated)
1941	Positive ground	6V (estimated)
1942	Positive ground	6V (estimated)
1946	Positive ground	6V (estimated)
1947	Positive ground	6V (estimated)
1948	Positive ground	6V (estimated)
1949	Positive ground	6V (estimated)
1950	Positive ground	6V (estimated)
1951	Positive ground	6V (estimated)
1952	Positive ground	6V (estimated)
1953	Positive ground	6V (estimated)
1954	Positive ground	6V (estimated)
1955	Positive ground	6V (estimated)
1956	Negative ground	12V (estimated)
1957	Negative ground	12V (estimated)

STUTZ

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

TERRAPLANE

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Positive ground	6V (estimated)
1935	Positive ground	6V (estimated)
1936	Positive ground	6V (estimated)
1937	Positive ground	6V (estimated)
1938	Positive ground	6V (estimated)
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Not listed	Not determined
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

TUCKER

Year	Ground polarity	Estimated voltage
1932	Not listed	Not determined
1933	Not listed	Not determined
1934	Not listed	Not determined
1935	Not listed	Not determined
1936	Not listed	Not determined
1937	Not listed	Not determined
1938	Not listed	Not determined
1939	Not listed	Not determined
1940	Not listed	Not determined
1941	Not listed	Not determined
1942	Not listed	Not determined
1946	Not listed	Not determined
1947	Not listed	Not determined
1948	Positive ground	6V (estimated)
1949	Not listed	Not determined
1950	Not listed	Not determined
1951	Not listed	Not determined
1952	Not listed	Not determined
1953	Not listed	Not determined
1954	Not listed	Not determined
1955	Not listed	Not determined
1956	Not listed	Not determined
1957	Not listed	Not determined

WILLYS

Year	Ground polarity	Estimated voltage
1932	Negative ground	6V (estimated)
1933	Negative ground	6V (estimated)
1934	Negative ground	6V (estimated)
1935	Negative ground	6V (estimated)
1936	Negative ground	6V (estimated)
1937	Negative ground	6V (estimated)
1938	Negative ground	6V (estimated)
1939	Negative ground	6V (estimated)
1940	Negative ground	6V (estimated)
1941	Negative ground	6V (estimated)
1942	Negative ground	6V (estimated)
1946	Negative ground	6V (estimated)
1947	Negative ground	6V (estimated)
1948	Negative ground	6V (estimated)
1949	Negative ground	6V (estimated)
1950	Negative ground	6V (estimated)
1951	Negative ground	6V (estimated)
1952	Negative ground	6V (estimated)
1953	Negative ground	6V (estimated)
1954	Negative ground	6V (estimated)
1955	Negative ground	6V (estimated)
1956	Not listed	Not determined
1957	Not listed	Not determined

“Not listed” means the source chart does not cover that make and year. “Varies” means the specific vehicle needs verification. Neither label confirms voltage or polarity.

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