#include <a_samp>
public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
if ((newkeys==KEY_ACTION)&&(IsPlayerInAnyVehicle(playerid))&&(GetPlayerState(playerid)==PLAYER_STATE_DRIVER))
{
if (GetVehicleModel(GetPlayerVehicleID(playerid)) == 525)
{
   SendClientMessage(playerid,0xFFFF00AA,\"trying to tow a car\");
   new Float:pX,Float:pY,Float:pZ;
   GetPlayerPos(playerid,pX,pY,pZ);
   new Float:vX,Float:vY,Float:vZ;
   new Found=0;
    new vid=0;
   while((vid<MAX_VEHICLES)&&(!Found))
   {
      vid++;
      GetVehiclePos(vid,vX,vY,vZ);
      if  ((floatabs(pX-vX)<7.0)&&(floatabs(pY-vY)<7.0)&&(floatabs(pZ-vZ)<7.0)&&(vid!=GetPlayerVehicleID(playerid)))
      {
         Found=1;
         if  (IsTrailerAttachedToVehicle(GetPlayerVehicleID(playerid)))
         {
            DetachTrailerFromVehicle(GetPlayerVehicleID(playerid));
                 }
         AttachTrailerToVehicle(vid,GetPlayerVehicleID(playerid));
         SendClientMessage(playerid,0xFFFF00AA,\"Car towed!\");
      }
   }
}
}
return 1;
}

 
Angol fórumon találtam, nem teszteltem.