500SEL (126.037) V8-5.0L (117.963) (1984)
Reserve Power Source: Description and Operation
Design: The reserve power source, also referred to as the buffer battery, is located in a separate housing connected with the control unit by means of a
cable harness.
Method of Operation: Should the vehicle battery fail immediately in the event of a collision, the control unit and the ignition circuits are supplied
from a reserve power source.
Failures of the reserve power source are indicated by the warning lamp in the instrument cluster.