Charging System - Basic Test Reminders
83mercedes01TO: OUR MERCEDES-BENZ PASSENGER DEALERS
DATE: September, 1983 REF.NO. MBNA 15/1
SUBJECT: HIGH NUMBER OF UNNECESSARILY REPLACED ALTERNATORS AND VOLTAGE REGULATORS
Recent inspections of electrical parts returned under warranty have shown that a high number of alternators and voltage regulators are being replaced unnecessarily. In all such cases, additional components, i.e. battery, starter, ignition switch or neutral safety switch, are also replaced..
The importance of proper testing and diagnosis of the battery, starting, and charging system cannot be over-emphasized. Our Warranty Dept. has instituted a program whereby the above mentioned components will be tested, and if found to be in working order, returned to the respective dealer with the warranty claim denied.
To avoid unnecessary replacement of electrical system components, be sure that all technicians are familiar with the following procedures:
1. Battery hydrometer test
2. Battery charging
3. Battery performance test
4. Battery drain tests
a. Key "off" drain test
b. Key "on" drain test
5. Starting system current draw test
6. Key switch/solenoid circuit test
7. Starter "hot" circuit test
8. Starter "ground" circuit test
9. Charging system tests
a. Maximum output test
b. Diode/stator test
c. Voltage regulator test
For additional information, refer to Service Information 15/14, April 1980.
If you have any questions concerning these procedures, please contact your MercedesBenz Field Service Manager.