VW Diesel Glow Plug Relay - Vemo 321911261C

Diesel engines do not use the typical spark plug found in gas engines to ignite the fuel. Instead, they use the heat of cylinder compression. When a diesel engine becomes cold it loses heat from compression which makes it difficult to start. Glow plugs which are located at each cylinder are essentially heating elements that electronically produce heat within the cylinder helping diesel engines to achieve the high heat temperatures required for the diesel fuel to be ignited. Throughout the life of your vehicle, the glow plugs, and other glow plug components within the circuit, can become faulty causing your vehicle to produce a hard starting condition. If you're experiencing a hard start condition on your VW TDI, we recommend inspecting the glow plugs, and secondary components such as this glow plug controller, often called the glow plug relay, and replace as necessary.