How To Access Drop Down List From Code Behind

I have an .aspx file that has 3 drop down lists:

ddlMake
ddlModel
ddlColour

i have a Page_Load function but i cant acces them in the Page_Load function...

using System;
using System.Collections.Generic;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

namespace NorthwindCascading
{
public partial class _IndexBasic : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
CarService service = new CarService();
List<string> Makes = service.GetCarMakes();
ddlMake.DataSource = Makes;
ddlMake.DataBind();
ddlMake.Items.Insert(0, " -- Select Make -- ");
}
}
}
}

I have added the code-behind file manually so i guess i am missing something... it just says that the ddlMake element is not defined in current context.