GM/Detroit 6.5L – ELECTRICAL TESTS

Before performing the diagnosis procedures on the vehicle, make sure the system wiring is good and the belt is not slipping. Also, the battery must be fully charged for a valid test of the charging system.

NOTICE: To avoid damage to the vehicle electrical system, observe the following pre­ cautions:
• Do not polarize the generator.
• Do not short across or ground any of the terminals in the charging circuit except as specifically instructed herein.
• NEVER disconnect the output terminal while the generator is operating.
• Make sure the generator and battery have the same ground polarity.
• When connecting a charger or booster bat­tery to the vehicle battery, connect nega­tive to negative and positive to positive.