Noise from a generator may be caused by a loose drive pulley,
loose mounting bolts, worn or dirty bearings, defective diode, or a defective
stator. A high frequency whine or magnetic noise may be heard at full
output. This is a normal condition.
Perform an output test in order to help distinguish bearing noise from
the magnetic noise, also called a whine. Refer to
Generator Not Operating Properly
. A shorted bridge diode will reduce output
be 1/3 of the rating and have a growling noise when at high load. It
is also helpful to listen to the generator with a moderate load (engine
cooling fans or headlights ON) in order to determine if there is a bearing
or magnetic noise.
In order to avoid damage to the electrical equipment, observe the following
precautions:
| • | Do not reverse the connections to the generator. |
| • | Do not short across or ground any of the terminals in the charging
circuit except as directed by the service manual. |
| • | Do not apply the battery voltage directly to the regulator L terminal
for testing. A 400 - 500 ohm resistor must be used. |
| • | Never disconnect the battery cables from the output terminal or
the battery while the generator is operating. |
| • | When connecting a charger or booster battery to the car battery,
refer to
Battery Charging
. |
Trouble in the charging system can be detected by the following conditions:
| • | The charge indicator does not light with the ignition switch in
the ON position before the engine start, or does not go out after the engine
start. The driver information center displays Check Charging System. |
| • | Service Engine Soon light comes on. |
| • | An overcharged battery as evidenced by spewing of electrolyte
from the vents. |
If an undercharged or overcharged battery condition occurs, the following
procedure may be used to diagnose the charging system:
- Visually inspect the accessory drive belt for damage or looseness.
- Check for proper belt tension.
- Inspect the charging circuit electrical connections for damage
or looseness.
- Perform the Generator Electrical Test. Refer to
Generator Not Operating Properly
.
