TM  5-5420-226-20-1 Symptom-2 DETAILED TROUBLESHOOTING PROCEDURE VEHICLE OPERATION -  POWERPLANT, STARTING (Continued) i v WARNING . Do   not   touch manifold heaters with bare hands. t ( h I Check intake manifold preheater for   operation. Both Technicians (Rear Grille Doors) l   Install    quick   disconnect and    connect fuel    return line. l   Install    transmission shroud (page 9-6). First Technician (Top Deck) l   Open   left   and   right   top    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 switch, MANIFOLD PREHEAT switch, and    operate PRIMER PUMP. Do    not    hold switches on   for   more than 14  seconds. First Technician (Top Deck) l   Reach    down   through grille door openings and feel for   heat from intake manifold preheater. Are   both    intake manifold preheater warm? 1 n ACCESS TO    INTAKE MANIFOLD PREHEATER (HIDDEN) ( I VIEW    THROUGH LEFT GRILLE DOORS 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. TA1O( . 15 4-126