My RR defroster on my 96 Aurora quit on me. The button does not lite-up, all fuses are ok - checked with an ohm meter. Also checked wiring harness in trunk. The dealer diagnosed a defective power module behind the dashboard and would cost about $1600 to replace. The component is also integrated with the heater/ac/auto climate control which are working. Has anyone seen this problem? Can the unit be repaired? The part cost $800 from dealer. I'm open to any suggestions. Thanks