TM    5-5420-226-20-1 ( ( Symptom-8 DETAILED TROUBLESHOOTING PROCEDURE VEHICLE OPERATION -  POWERPLANT, STARTING (Continued) FROM   STEP o 2 1 #check for  electrical   power  to  manifold  heater  ignition unit  (CKT  486). First l l l Technician (Powerplant) Disconnect engine electrical harness connector from manifold heater ignition unit    at   cold    manifold heater. Set  multimeter to  measure 18 to  30  volts   dc,  or  use  STE/ ICE    Test No. 89   (page 4-81). Connect red   probe    of  meter to  contact A  (CKT 486)   of engine electrical harness connector at   manifold heater ignition unit    and    black probe to   ground. Second Technician (Operator’s Station) l l First l Set   MASTER BATTERY switch ON. Press STARTER and    preheat switches at   the    same time, hold on   for   approximately 10  seconds, then release. Technician (Powerplant) Check if   meter indicates 18  to   30   volts    dc. Does  meter   indicate   18  to  30  volts  dc? ‘ l   Repair   engine   electrical    harness (CKT   486)  (page   10-298). I l   Connect   high  voltage   ignition P NO lead  to  spark   plug. C^OB    ~o ,illl lD* II^CONTACTA (CKT    486) IGNITION UNIT RIGHT SIDE    OF   ENGINE SHOWN I I I ENGINE DISCONNECT PM ““oN I TA1069O7 4-218