TM 9-2320-280-20-1 KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION KNOWN INFO POSSIBLE PROBLEMS TEST OPTIONS REASON FOR QUESTION NO YES YES NO YES ALTERNATOR 2-198           Change 1 4 5 6 START ENGINE.  DOES ENGINE IDLE AT CORRECT SPEED (6.2L 625-675 RPM)? (6.5L 700-750 RPM)? LOCK THROTTLE AT 1200-1500 RPM. IS VOLTAGE AT ALTERNATOR OUTPUT TERMINAL 27-29 VOLTS ? IS VOLTAGE AT BATTERY TERMINALS 27-29 VOLTS ? (SAME AS ALTERNATOR OUTPUT) STE/ICE-R TEST 10 (Page 2-734) BATTERIES OK BELTS OK ALTERNATOR CONNECTIONS OK PCB/DISTRIBUTION BOX   OK ALTERNATOR ALTERNATOR DRIVE WIRING If engine idles too low, alternator is not driven fast enough to charge batteries. Alternator voltage must be slightly higher than battery voltage to recharge batteries. 1. STE/ICE-R TEST 10 (interleave     with control function 01 page        2-734) thru 89, page 750 2. MULTIMETER BATTERIES OK BELTS OK ALTERNATOR CONNECTIONS OK PCB/DISTRIBUTION BOX OK ALTERNATOR DRIVE OK ALTERNATOR WIRING 1. STE/ICE-R TEST 67 (Page 2-740) 2. MULTIMETER If battery voltage is much lower than alternator output, wiring resistance is too high. BATTERIES OK BELTS OK ALTERNATOR CONNECTIONS OK PCB/DISTRIBUTION BOX OK ALTERNATOR DRIVE OK ALTERNATOR OUTPUT OK ALTERNATOR WIRING REPAIR/REPLACE WIRING SEE NOTE AT RIGHT ADJUST IDLE RPM SEE NOTE AT RIGHT GO TO 7, Page 2-200 FROM 3, Page 2-196 GO TO B, Page 2-204 DIAGNOSTIC FLOWCHART NO