TM    9-2330-238-14 2-10.    COUPLING SEMITRAILER TO  TOWING    VEHICLE (Con’t). Remove dummy couplings (2)  from   semitrailer service air   coupling (1)   and   semitrailer emergency air coupling   (3). d. Connect towing vehicle service air  coupling (7)  to   semitrailer service air  coupling (1).   Connect    towing vehicle emergency air  coupling (6)  to   semitrailer emergency air  coupling (3). e. Ensure that air   reservoir draincock (8)   is closed.    Turn on  two  towing   vehicle    air  line  shut-off   valves to   apply pressure as   required (refer   to   towing vehicle technical manual). Connect intervehicular cable (5)   into   semi- f. trailer   receptacle (4) on  front  of  semitrailer.    Ensure  that  all lights   are  working properly. 2-11.    UNCOUPLING SEMITRAILER FROM   TOWING    VEHICLE. WARNING a. b. All  personnel must   stand   clear   of  towing    vehicle and   semitrailer during   uncoupling operation. Failure    to   follow this   warning may    result    in   serious injury    or   death    to personnel. Chock    semitrailer wheels and   raise   front   of  semitrailer using   landing    gear   (para   2-12). Disconnect towing   vehicle    service   air  coupling (7) from   semitrailer service   air  coupling (1)  and  disconnect towing    vehicle emergency air  coupling (6)  from   semitrailer emergency air  coupling (3). TA701914 2-10