[Whizion]

Try this:

pawn Код:

forward Haz_Timer();

public Haz_Timer()
{
    for(new i = 0; i < MAX_PLAYERS; i++)
    {
        if(IsPlayerConnected(i) && IsPlayerInAnyVehicle(i))
        {
            if(GetPVarInt(i, "VehLightStatus") > 0)
            {
                SetVehicleParamsEx(GetPlayerVehicleID(i),engine,0,alarm,doors,bonnet,boot,objective);
                SetPVarInt(i, "VehLightStatus", 0);
            }
            else
            {
                SetVehicleParamsEx(GetPlayerVehicleID(i),engine,1,alarm,doors,bonnet,boot,objective);
                SetPVarInt(i, "VehLightStatus", 1);
            }
        }
    }
    return 1;
}

dcmd_hazards(playerid, params[])
{
    if(IsPlayerInAnyVehicle(playerid))
    {
        new veh = GetPlayerVehicleID(playerid);
        SetVehicleParamsEx(veh,engine,1,alarm,doors,bonnet,boot,objective);
        SetPVarInt(playerid, "VehLightStatus", 1);
        return 1;
    }
    return 0;
}

EDIT:

You should also put this:

pawn Код:

SetTimer("Haz_Timer", 500, true);

Under:

pawn Код:

OnGameModeInit()