It sounds like your charger is not working. Do you have a meter? The cheap ones work just as well as the expensive ones. You can usually get them at most hardware stores. Get a digital one, one that is rated to 600V so that you can use it elsewhere.
With you meter on DC. What is your battery voltage? You can measure this right on the battery across the terminals. When you plug in your TT does the charge voltage increase? If you do the same test on you car you can see what the results should be (roughly). If the charge voltage does not go up then either you have a blown fuse or the charger is not working, or your battery still does not work. Some TTs have an inline fuse at the battery check that. If nothing is you kill switch off (if you have one)? Bottom line you will have to follow the wires back and take some measurements to isolate and debug this.