Rectifier Bridge (Cs-121)
- With alternator disassembled, connect one ohmmeter lead to grounded heat sink (closest to outside of alternator housing). Connect second ohmmeter lead firmly against flat metal portion of terminal connector (not threaded stud). See Fig 1. Reverse leads to same heat sink and terminal. If readings are identical, replace rectifier bridge.
Courtesy of GENERAL MOTORS CORP.
- If one high and one low reading is obtained, rectifier bridge is okay. Repeat test between grounded heat sink and 2 flat metal connectors. Test between insulated heat sink (closest to inside of alternator) and each of the 3 flat metal connectors.
- Check remaining bridge rectifiers in same manner. DO NOT
replace rectifier bridge unless one pair of readings are the same.