The 4WD indicator near the speedometer of your Scorpio SLX CRDe 2007 model is for the top end variant with 4 wheel drive available. Companies use the same instrument consoles on all the models ranging from base to the top in order to save more on the production cost. Most of the manufacturers provide all the feature displayed on the console whose power supply has only been provided in the desired model. This saves a lot of money and work for them. The common indicators which are made but works in the top model are the airbag, ABS and 4WD. It will never glow as it works only in the top model of the car.