Notes: 4 Glow Plugs & Relay Bosch has superseded the glow control relay to a new glow plug kit which includes a new controller and 4 glow plugs. This new controller allows the glow plugs to continue functioning up to 3 minutes after the vehicle has been started, providing a smoother engine start up and less exhaust smoke. It is important to keep this in mind when testing the glow circuit func- tionality. For vehicles with 5 cylinders, 1 additional glow plug is required (0 250 201 039).