Generator & Regulator Switch

WARNING: This page is about a different car, the 2005 BMW 530i, 2005 BMW 525i, 2004 BMW 530i, and 2004 BMW 525i. However, it is still accessible from the selected car via links, so may be relevant.

Check for correct connections on fully charged battery, generator and starter motor. Check for good ground connection between engine and body. Check for properly tightened drive belt. Connect DIS tester. Search down through the following:

Function Selection
Complete Vehicle
Drive
Voltage And Current Regulation
Voltage And Current Generation

Work through test modules. To diagnose oscillograms for each fault, see GENERATOR OSCILLOGRAMS . If generator is faulty, repair or replace it. To replace, see GENERATOR under REMOVAL & INSTALLATION.

GENERATOR OSCILLOGRAMS

Fault	Oscillogram
Fault-Free	See Fig 1
One Phase Interrupted	See Fig 2
Internal Fault	See Fig 3
Open Circuit In Negative Diode	See Fig 4
Short Circuit In Positive Diode	See Fig 5
Open Circuit In Positive Diode	See Fig 6
Open Circuit In Exciter Diode	See Fig 7