TEST OPTIONS REASON FOR QUESTION If battery(ies) is unserviceable, 12 vdc circuits will not operate. KNOWN INFO e89.  ELECTRICAL SYSTEM DOES NOT MAINTAIN A CHARGE POSSIBLE PROBLEMS 1. Are batteries serviceable? WARNING Read WARNING on following page. START NO Engine oil pressure indicator   light illuminates. OIL PRESS gage operates. Engine starts. Alternator belts OK. YES Charge battery(ies) (TM 9-6140-200-14) or replace battery(ies) (para 7-46). Faulty battery(ies). Faulty engine oil pressure switch. Faulty relay K11. Faulty dashboard cable assembly. Faulty engine control cable assembly. Faulty alternator ground strap. Faulty alternator. Faulty voltage regulator. Faulty 100 AMP alternator to reverse polarity relay 12 vdc cable. Faulty 200 AMP alternator to terminal block 12 VDC cable. Faulty 100 AMP alternator to reverse polarity relay 24 VDC cable. Faulty 200 AMP alternator to terminal block 24 VDC cable. Battery Specific Gravity Test TM 9-2320-365-20-1 2-1010         Change 1 INITIAL SETUP   Equipment Conditions     Engine shut down (TM 9-2320-365-10).   Materials/Parts     Wire, Elect, 50 ft (Item 77, Appendix D)     Wire, Relay Test (Item 9, Appendix E)     Nut, Self-Locking (Item 131.1, Appendix G) (100 AMP)     Nut, Self-Locking (Item 130.1, Appendix G) (200 AMP) References    TM 9-6140-200-14    TM 9-4910-571-12&P Tools and Special Tools   Tool Kit, Genl Mech (Item 44, Appendix C)   STE/ICE-R (Item 39, Appendix C)   Multimeter, Digital (Item 22, Appendix C)   Apron, Rubber (Item 3, Appendix C)   Gloves, Rubber (Item 13, Appendix C)   Goggles, Industrial (Item 15, Appendix C)   Tester, Antifreeze and Battery (Item 41, Appendix C)   Wrench, Torque, 0-200 lb-in. (Item 58, Appendix C)   Personnel Required     (2)