TM 5-5420-226-20-1 Symptom-3 DETAiLED TROUBLESHOOTING PROCEDURE VEHICLE OPERATION -  POWERPLANT, STARTING (Continued) ~ NOTE If   outside air    temperature is   above 4(Y,   go   to   Step ~ WARNING 1 Do not touch manifold preheater with    bare hands. J_{Checkmanifold} preheater for    heat. First Technician (Top Deck) l   Open   left   and   right   top    deck   grille   doors. Second Technician (Operator’s Station) l   Set   MASTER BATTERY switch ON. l   Set    FUEL PUMPS switch ON. l   At    the    same   time,   press   STARTER BUTTON, PREHEAT SWITCH and    operate primer pump. Do not    hold switches on   for   more than 14  seconds. First Technician (Top Deck) l   Reach    through grille door opening and feel   for   heat from manifold preheater (left    and right side). l   Check  if  heat   comes   from   both   manifold preheater. Second Technician (Operator’s Station) l   Set   MASTER BATTERY switch OFF. Does heat    come from both    manifold preheater? VIEW THROUGH LEFT GRILLE DOORS ( I ) l   If   both    preheater are   cold, See    Symptom 9:   BOTH INTAKE MANIFOLD PREHEATER WILL NOT WORK. l    If   only    one    preheater is   cold, See    Symptom 8:  ONE INTAKE MANIFOLD PREHEATER WILL NOT WORK. TA106843 4-154