TM 9-2320-361-20 4-36. FRONT-WHEEL DRIVE LOCK-IN SWITCH INDICATOR AND AIR PRESSURE SWITCH REPLACEMENT (Contd) FOLLOW-ON TASKS: Connect battery ground cable (para. 4-48). Start engine (TM 9-2320-361-10) and allow air pressure to build up to normal operating range. Check for air leaks at switch. Engage front-wheel drive lever (TM 9-2320-361-10) and check if indicator light is illuminated. 4-55