[CoaPsyFactor]

pawn Код:

stock GetVehicleTrailerPos(vehicleid, trailerid, &Float:x, &Float:y, &Float:z){
    if(IsTrailerAttachedToVehicle(vehicleid)){
        if(GetVehicleTrailer(vehicleid) == trailerid){
            GetVehiclePos(trailerid, x, y, z);
            return 1;
        }else{
            return 0;
        }
    }else{
        return 0;
    }
}

so this is function that can return position of trailer that is attached to some vehicle.
Usage:

pawn Код:

GetVehicleTrailerPos(vehicleid,GetVehicleTrailer(vehicleid), mx, my, mz);
            new mstring[128];
            format(mstring, sizeof(mstring), "%f | %f | %f |", mx, my, mz);
            SendClientMessage(playerid, COLOR_SYSTEM, mstring);

i want to thanks to Donny_K for little help.