TM  10-3930-669-20 1.  DRIVE AXLE OVERHEATING (CONT). KNOWN INFO Engine temperature 105° F or over. Glow plug indicator operates. Parking brake OK. Brake fluid OK. Drive axle oil level correct. Master cylinder OK. Drive axle OK. Axle oil pump ground wire OK. Axle oil pump OK. Relay R8 ground wire OK. Wire 29 to relay R8 OK. Wire 74 OK. Relay R8 OK. Wire 29 to drive axle temperature switch OK. Drive axle oil temperature switch OK. Wire 72 OK. Drive axle oil cooler ground wire OK, Drive axle oil cooler OK. Relay R7 ground wire OK. Wire 29 to relay R7 OK. Wire 73 OK. Relay R7 OK. Wire 29 to engine temperature switch OK. POSSIBLE PROBLEMS Engine temperature switch faulty. Wire 71 faulty. TEST OPTIONS Voltage test. STEACE-R #89. REASON FOR QUESTION If   22   to   24   vdc   are   not   present, engine  temperature  switch  is  faulty. If temperature switch is OK, wire 71 is faulty. 2-360