My car is a Mitsubishi Magna TH 1999 3.5L Auto.
The alternator gives no voltage at idle with headlights & fan on. The battery gets drained. The alternator warning light pops up. If revved a little bit, I get 13.4 volts and no warning light. Without load, 13.4 v at idle and 14.3 v at 1000 rpm. When the engine is off the battery shows 12.4 v when connected and disconnected.
When bench testing, the diodes read 475mv one way. The alternator reads 670mv one way when the black probe is to the alternator positive and the red probe to the body.
Is the regulator faulty? The brushes still look good.
Please advise me. Thanks in advance.
P.S. I checked the voltages again this morning when the engine was cold. I fully charged the battery with an external charger and it read 13 v. I measured around 14.3 v without load and 13.3 v with load. But it was 11 v after the engine had reached the normal temp.