Generator Noise Test

Noise from a generator may be caused by any of the following:
- A loose drive pulley
- Loose mounting bolts
- Worn or dirty bearings
- A defective diode
- A worn stator

A high frequency whine or magnetic noise may be heard at full output. This is a normal condition. Perform a generator output test in order to help distinguish bearing noise from magnetic noise or whine. Refer to Charging System Check. System Check - Charging System

A growling noise under a high load condition could indicate a shorted bridge diode. A generator with a shorted diode will also have a reduced output. Perform a generator output test. Refer to Charging System Check System Check - Charging System

It is also helpful to listen to the generator under a moderate load (i.e. headlights ON) in order to determine if there is a bearing or magnetic noise.
Do not disassemble the CS 130D generator. Generator service is limited to replacement only. Refer to Generator Replacement. Service and Repair