This car had an interesting story. The car presented with the charging light on, indicating alternator failure. The alternator light would flicker, turning on and off rapidly. Alternator failures are somewhat uncommon on the later Volvo S70s, but a charging system analysis showed that the alternator was indeed not charging under load, even when full fielded. 12 VDC was found at the field wire during the testing. We replaced the alternator with a Bosch remanufactured unit and then road tested the car. The alternator light came back on, but was steady, not flickering as before. We checked for voltage on the field wire, no voltage.
A check of the schematic showed that the field wire was powered up via the dashboard and indicator. We tried tapping on the dash and noted that the light would go out. We removed and inspected the instrument cluster, no fault found. The tech then followed the harness down under the dash and found a poor connection at a large multi-block connector. Correction of this fault corrected the charging issue and the new alternator will not fail or become quickly damaged like the former unit.
