TM 10-3930-669-20 2-14.  ELECTRICAL SYSTEM TROUBLESHOOTING (CONT). 13.  GAUGE LIGHT DOES NOT OPERATE. INITIAL SETUP Tools and Special Tools Tool Kit, General Mechanic's:   Automotive (Item 1, Appendix B) Multimeter (Item 2, Appendix B) STE/ICE-R (Optional) (Item 14, Appendix B) References TM 10-3930-669-10 Equipment Condition Engine OFF (TM 10-3930-669-10) MAIN POWER switch OFF (TM 10-3930-669-10) Parking brake applied (TM 10-3930-669-10) Wheels chocked (TM 10-3930-669-10) NOTE The following troubleshooting procedures cover the engine oil temperature gauge light, but they can apply to any gauge light. KNOWN INFO TEST OPTIONS Front    floodlight,    mastlight, and other gauge lights operate. Continuity test. STE/I1CE-R #91. POSSIBLE PROBLEMS REASON FOR QUESTION Gauge lamp faulty. Gauge wire 25 faulty. If   continuity   is   not   present, gauge    lamp    is    faulty.        If gauge   lamp   is   OK,   gauge wire 25 is faulty. 2-194