D Group 37 Wiring diagram Component wiring diagram FH12, FH16 LHD Central lock Power take-off Double power take-off Diff. lock Lock, 3rd axle, bogie lift Lock, 3rd axle Geartronic Bogie lift (hydraulic) Bogie lift (hydraulic), with axle load limiter Air suspension 4x2 Bogie lift, air suspension 15 tonnes Air suspension 6x2 15 tonnes with time limitation Bogie lift, pusher Bogie lift, air suspension tonnes 4