[RedFusion]

So you are asking about entering a trailer?
You must assign an ID to the trailer.

pawn Код:

new trailer;

pawn Код:

OnGameModeInit()
{
trailer = CreateVehicle(cords and stuff..)

}

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    if (strcmp("/gototrailer", cmdtext, true, 10) == 0)
    {
        PutPlayerInVehicle(playerid,trailer,0);
        return 1;
    }
    //Other cmds here
    return 0;
}

I think this would work.