Hi Frank, most likely you need new glow plugs. The glow plug circuit should be tested to make sure the plugs are receiving power with the key on. If they are, and your glow plug light is not coming on with the key, it's an indication of one or more bad glow plugs. The individual plugs can be tested to see which are bad but it's often best to replace all of them. When replacing the glow plugs it's important to clean the glow plug chambers before installing the new plugs. Let me know if you have any questions.