GENERATOR & REGULATOR SWITCH
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 generator on 3.0L (M54), see
GENERATOR 3.0L (M54)
under REMOVAL & INSTALLATION. To replace generator on 4.4L & 4.6L (M62), see
GENERATOR 4.4L & 4.6L (M62)
under REMOVAL & INSTALLATION. To replace generator on 4.4L (N62), see
GENERATOR 4.4L (N62)
under REMOVAL & INSTALLATION.
If regulator is faulty, replace it. To replace Bosch regulator, see VOLTAGE REGULATOR (BOSCH) . To replace Valeo regulator, see VOLTAGE REGULATOR (VALEO) . To replace regulator on 4.4L (N62) see VOLTAGE REGULATOR 4.4L (N62) .
| Fault | Oscillogram |
|---|---|
| Fault-Free | (Scheme 53) |
| One Phase Interrupted | (Scheme 54) |
| Internal Fault | (Scheme 55) |
| Open Circuit In Negative Diode | (Scheme 56) |
| Short Circuit In Positive Diode | (Scheme 57) |
| Open Circuit In Positive Diode | (Scheme 58) |
| Open Circuit In Exciter Diode | (Scheme 59) |
GENERATOR OSCILLOGRAMS
Scheme 53
Scheme 54
Scheme 55
Scheme 56
Scheme 57
Scheme 58
Scheme 59
A/C COMPRESSOR DRIVE BELT 3.0L (M54)
Note. If drive belt is to be reused, mark direction of travel and reinstall drive belt in same direction.
A/C COMPRESSOR DRIVE BELT 4.4L (N62)
Note. If drive belt is to be reused, mark direction of travel and reinstall drive belt in same direction.
Note. If drive belt is contaminated with hydraulic fluid, replace it.
FAN CLUTCH
Note. Fan clutch bolts have left-hand threads.
GENERATOR 3.0L (M54)
| CAUTION | Disconnecting vehicle battery will cancel fault codes of control units. On vehicles with radio codes, after disconnecting battery, radio codes must be re-entered. Obtain radio code card from customer. Note stored stations and restore them after connecting battery. Also, where applicable, initialize sunroof and set steering angle. |
GENERATOR 4.4L & 4.6L (M62)
| WARNING | Danger of scalding! Only perform procedures on engine that has cooled down. |
| CAUTION | Disconnecting vehicle battery will cancel fault codes of control units. On vehicles with radio codes, after disconnecting battery, radio codes must be re-entered. Obtain radio code card from customer. Note stored stations and restore them after connecting battery. Also, where applicable, initialize sunroof and set steering angle. |
GENERATOR 4.4L & 4.8L (N62)
| WARNING | Danger of scalding! Only perform tasks on an engine that has cooled down. |
| CAUTION | Disconnecting vehicle battery will cancel fault codes of control units. On vehicles with radio codes, after disconnecting battery, radio codes must be re-entered. Obtain radio code card from customer. Note stored stations and restore them after connecting battery. Also, where applicable, initialize sunroof and set steering angle. |
Note. A small amount of coolant emerges when generator is removed from housing. Catch and dispose of escaping coolant observing appropriate waste disposal regulations.
Note. There are no vent plugs on radiator or thermostat housing. Cooling system is bled while filling and during subsequent idle operation.
Note. For purposes of clarity, some procedures are shown in figures after component has been removed.
GENERATOR DRIVE BELT 3.0L (M54)
Note. If drive belt is to be reused, mark direction of travel and reinstall drive belt in same direction.
GENERATOR DRIVE BELT 4.4L & 4.6L (M62)
Note. If drive belt is to be reused, mark direction of travel and reinstall drive belt in same direction.
GENERATOR DRIVE BELT 4.4L & 4.8L (N62)
Note. If drive belt is to be reused, mark direction of travel and reinstall drive belt in same direction.
VOLTAGE REGULATOR (BOSCH)
| CAUTION | Disconnecting vehicle battery will cancel fault codes of control units. On vehicles with radio codes, after disconnecting battery, radio codes must be re-entered. Obtain radio code card from customer. Note stored stations and restore them after connecting battery. Also, where applicable, initialize sunroof and set steering angle. |
VOLTAGE REGULATOR (VALEO)
| CAUTION | Disconnecting vehicle battery will cancel fault codes of control units. On vehicles with radio codes, after disconnecting battery, radio codes must be re-entered. Obtain radio code card from customer. Note stored stations and restore then after connecting battery. Also, where applicable, initialize sunroof and set steering angle. |
VOLTAGE REGULATOR 4.4L (N62)
| CAUTION | Disconnecting vehicle battery will cancel fault codes of control units. On vehicles with radio codes, after disconnecting battery, radio codes must be re-entered. Obtain radio code card from customer. Note stored stations and restore them after connecting battery. Also, where applicable, initialize sunroof and set steering angle. |
Note. Manufacturer may refer to component as controller switch.