TM 10-3930-669-20 1.  DRIVE AXLE OVERHEATING (CONT). KNOWN INFO TEST OPTIONS 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. 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. Engine temperature switch OK. Wire 71 OK. Axle oil pump ground wire OK. Axle oil pump OK. Wire   29   to   drive   axle   temperature switch OK. Drive axle oil temperature switch OK. Wire 72 OK. Continuity test. STE/ICE-R #91. POSSIBLE PROBLEMS REASON FOR QUESTION Relay R8 ground wire faulty. Wire 29 to relay R8 faulty. Wire 74 faulty. Relay R8 faulty. If  continuity  is  not  present,  relay R8 ground wire is faulty. ¬ 2-368