TM 9-2320-279-10-1 Change 8 2-10.3 Controls and Indicators (Cont) Figure 2-5.1. (FHTV Only) Instrument Panel Controls and Indicators (Sheet 3 of 3). Key Control or Indicator Function 21 Engine Start Switch Three position switch. Straight up is OFF position. ON position operates electrical system. START position operates engine cranking circuit. When switch is released after engine starts, switch will return to ON position. 22 LOW AIR Indicator Lights (red) and remains lit until airbrake air pressure in each section of dual system is between 60 psi (414 kPa) to 75 psi (517 kPa). Buzzer will sound anytime indicator is lit. 23 AIR PRESS Gage Shows air pressure (in psi and kPa) in both sections of airbrake system. Green needle shows front section air pressure. Red needle shows rear section air pressure. 24 BATTERY Gage Shows state of charge of batteries and alternator voltage output. 25 AMPERES Gage Shows alternator output in Amperes. 26 TRAILER AIR SUPPLY Control Charges trailer airbrake system. 27 DIGN REQ Switch Activates troubleshooting system used by maintenance to diagnose engine problems. 28 Oil/Water Indicator Lights (red) when oil pressure is low or water temperature is too high. 29 LHS Indicator (LHS Only) Lights (green) when Rotary Hydraulic Selector Switch is in auto, MAN H.A., or MAN M.F. positions. 30 LHS NO TRANSIT Indicator (LHS Only) Lights (red) when LHS is not correctly stowed in TRANSPORT position. 31 LHS OVERLOAD Indicator (LHS Only) Lights (yellow) when LHS has reached an overload condition or the hydraulic system is lifting very near maximum capacity.