Left hand driver car, OK So the yellow plug is for the trip/fuel computer. No need to worry about that as you mustn't have one fitted.

Your next step is to go to the car and remove the lid from the fusebox, look for the picture on the lid with heated seats fuse. Is it blown or removed? This isn't a heated seat fuse.... The lid was from the parts bin. This fuse is for the electronic fuel injection on start up when the engine is cold.