TM-9-2320-280-20 HMMWV Technical Manual Unit Maintenance Volume 1 Download
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REFERENCE INFORMATION The glowplugs first come ON when the engine temperature is below 120 °F (49 °C) and the rotary switch is turned to RUN. They stay ON for up to 9 seconds and then go OFF. They will stay OFF for about 7-15 seconds then come ON again for about 1 second, than go OFF again. If you don’t start the engine, the glowplugs should keep cycling like this, due to the glowplug cycle timer in the glowplugs controller. It you start the engine, they will cycle until the engine is warm, due to the afterglow cycle timer in the glowplug controller. When the engine gets up to 120 °F (49 °C), the glowplugs should stop cycling completely. ENGINE NOT RUNNING If the glowplugs are cycling property, you should hear a click from the protective control box (PCB) when the glowplugs turn on and when they turn off. This is the glowplug cycle timer, a thermal circuit breaker. A good way to check for cycling is STE/lCE-R test 80, battery current. When the glowplugs turn on, STE/lCE-R will measure 74-125 amps. When the glowplugs turn off, the STE/lCE-R will measure 3-8 amps. ENGINE RUNNING. ROTARY SWITCH IN RUN If the glowplugs are cycling properly, you can hear a click from the protective control box (PCB) when the glowplugs turn on and when they turn off (you may have to duck your head under the dash). This is the afterglow cycle timer, a thermal circuit breaker. A good way to check for cycling is STE/ICE-R test 80, battery current. When the glowplugs turn on, STE/lCE-R will measure 74-125 amps. When the glowplugs turn off, STE/lCE-R will measure 3-8 amps. As the engine gets warmer, the glowplugs turn on leas frequently and for baa time. NOTE If you don’t have a STE/lCE-R or a multimeter for measuring current, you can watch the vehicle volts gauge for indication of glowplug operation. The glowplugs drew so much current that the volts gage should jump about half-an-inch to the left when the glowplugs come on. Before starting the engine, you should hear the glowplug power relay click open and closed as the glowplugs cycle. (You can hear the relay after the engine has started by leaning your head under the dash near the protective control box.) This method won’t tell you if all the glowplugs are working property, but it at least shows that the glowplugs are trying to work and that the glowplug power relay is working. TM 9-2320-280-20-1 GLOWPLUGS 2-307