I have a 1987 240 sedan. The rear window defrost has not been working. The power supply to the window is fine. I notice the electrified metal bar that attached to the metal strip on the window - is somewhat corroded. The bar appears to be pressed against the window metal strip - for proper connection. Anyway, the metal strip on the window seems to be the problem - no proper connection. How do I repair the connection and how do I remove the trim piece between the rear glass and the rear side window - to access the electric wire, etc.